Dennis McCoy, a delegate from northeast Baltimore, is taking the optimist's view. As for as he is concerned, the 1979 Maryland legislature may be the most productive of this decade. "This just might be the most exciting time to be in Annapolis in a generation," he said. "I think we're going to do some very significant things right from the start."

Jack Garrity, the senator from Hyattsville, is looking at things from the opposite perspective, somberly predicting that the session will be utterly forgettable. "It will be a time of tinkering and adjusting," he said. "I doubt if much of substance will be accomplished around here."

In this instance, the great expectations of one politician and the pessimism of the other were based on the very same premise. Garrity and McCoy agreed that Wednesday, the opening day of this year's General Assembly, marks the introduction of a new political era in Maryland. The dispute concerns what sort of era it is going to be.

Garrity and some other veteran lawmarkers look into the future and see a capable but untested legislative leadership, led by House Speaker Benjamin L. Cardin and Senate President James Clark Jr., struggling to adjust to a new governor, Harry R. Hughes. Some legislators already believe Hughes may already have withdrawn too far from the give-and-take of politics to be an effective leader.

"I don't think Hughes has the ability to assert himself in the executive capacity," said Garrity recently. Paul Weisengoff, the leader of the Baltimore House delegation until a heart attack slowed him down this year, added: "When it comes to relations with us, Hughes has shown all the classic signs of getting off to a lousy start."

However, McCoy and other optimists in the legislature say that Hughes is merely planning to treat the General Assembly the way it always has wanted to be treated -- with respect.

"The governor has the constitutional right to guide, not to interfere," said McCoy. "For once, we'll have the freedom to exercise policy on our own -- and that's not something we should complain about."

Those who predict that this session will be productive also note that among the 188 legislators there will be 11 new senators and 53 new delegates along with the new governor.

"Some people think that the newcomers are unproductive until they learn the process, but I disagree completely," said Sen. John J. Bishop, a liberal Republican from Baltimore County.

"I think you tend to get significant legislation passed on that first year of the quadrennial, when the freshmen still have their ideals and imagination, before the lobbyists and pressures get to them," he added.

Bishop points to 1967, his freshman year in the legislature, as an example of what can be accomplished on what he calls "the first blush." It was during that year -- with a freshly-reapportioned legislature and a new governor, Spiro T. Agnew -- that Maryland enacted its only major postwar tax reform package.

There are ome legislators coming to Annapolis this year who are tired of "reform packages" and "significant legislation" and believe that the legislators might serve their constituents best by doing as little as possible over the next three months. "Most bills are spending bills," said Prince George's Sen. Thomas V. (Mike) Miller. The fewer bills we pass the less we'll spend."

This ode to frugality, once recited by only the most conservative of politicians, has, in this year after Proposition 13, become a part of almost every lawmaker's regular litany. And, as a consequence, the 1979 legislative docket is overflowing with bills to either cut taxes or limit government spending.

Several measures are aimed at limiting state spending to 7 percent yearly. Sen. Clark, the soft-spoken gentleman farmer from Howard County who will lead the Senate this year, organized the spending-cap movement last year and is back at the forefront once again.

The concept is supported by many legislators in Prince George's and Montgomery counties, where the Proposition 13 fever raged last fall, but leaders of the Baltimore delegation have promised to fight it.

"Just mandating a lid on spending is the wrong approach," said Walter Dean, a black delegate from Baltimore. "The most important thing is to reapportion the tax money we're bringing in and sending out."

Last year, in what was billed as an important tax reform, the legislature expanded a property tax credit program that gave subsidies to homeowners of limited income. Also known as the circuit-breaker program, it was intended to provide needy homeowners with a total of $22 million in credits. Instead, for reasons that have not been fully detailed, the state paid out only a total of $3 million.

As a result, one of the major objectives of this session, according to Speaker Cardin, the legislature's acknowledged tax authority, will be to find out what went wrong with the circuit-breaker, then correct and expand the program. Hughes supports this approach.

Cardin, who many believe will leave more of an imprint on this legislature than anyone else, personally supports changes in the state's income tax to provide for more tax brackets. Income tax reform is opposed by most of the suburban legislators in Prince George's, Montgomery and Baltimore counties, and Hughes also has been cool to a change in the income tax structure.

The one change in the income tax is seen as likely this year is an increase, in the standard deduction from $500 to a larger sum, possibly $1,500.

There also will be a lot of talk about Maryland going bankrupt, an unusual topic, it might seem, for a state now boasting a surplus in the $200 million range. But there are many legislators who believe the state pension system must be reformed if the state is to avoid going broke sometime in the future.

Clark, who sponsored the pension bill last year, will make another attempt at it this year.

One matter that will not be avoided -- and in fact may be handled the first week of the session -- concerns the interest rate on home mortgages in the state. There currently is a ceiling on the interest rate that lending institutions can charge for home mortgages -- 10 percent. Industry spokesman, and more and more politicians, charge that the ceiling is too low and the reason why only 86 of the 312 financial houses in the state offer home mortgages.

Several emergency bills to lift or raise the interest rate ceiling will be considered this week in the Senate.

As always, the 1979 session will have its share of dramatic confrontations between urban and rural interests. The questions at issue this year may be D.C. voting rights and subway financing. The constitutional amendment to give Washington a congressman and two senators is expected to be approved by the neighbors in Maryland, but not without some political maneuvering.

"I think on principle most of the suburban Washington legislators support the concept," said Robert Redding, chairman of the Prince George's delegation. "But there's a concern that voting rights for the District of Columbia will be followed by a commuter tax for suburban workers in the city. We've got to work for an agreement that that won't happen."

The Washington suburbs and Baltimore will be asking for state assistance of one sort or another to expand the subway systems in the two areas. Funding for the Baltimore subway system, which is entirely state-financed and operated, is expected to be included in the administration budget. Sen. Fred Malkus, the Eastern Shore legislator who long has opposed that subway's financing, has promised to filibuster the measure this year.

"But I'll leave Washington Metro alone," said Malkus. "I can only fight one battle at a time."