QUITE PROPERLY underwhelmed by their collective accomplishments this year, members of Virginia's General Assembly may take modest comfort in the knowledge that the session did pefer out with relatively little damage put on the books. In the end-of-session account by Richmond correspondents Paul G. Edwards and Bill McAllister in this newspaper, the brief epilogue offer by Del. Thomas W. Moss (D-Norfolk) pretty much summed things up: "I don't think this session will go down as one of the great ones," he said. "Did the commonwealth get its money's worth from us? Overall, I'd say it was about a break-even deal."

Even Gov. Mills E. Godwin, who deserves a generous share of credit for the mediocre output, acknowledged the absence of memorable achievements. "If no permanent solutions have been forthcoming," he said delicately in his farewell to the lawmakers. "the groundwork has been laid for informed and deliberate choices when next you meet. If in some instances the tendency has been to put off difficult decisions, you will have the reaction of the people themselves as your guide henceforth."

What the governor didn't add, of course, was that this unfortunate legacy of "difficult decisions" stems in no small measure from his reluctance to exercise forecful leadership in dealing with the budget.After seeing his tax package to finance college and other construction spurned by the House of Delegates last year, Mr. Godwin waited around this time for some sort of consensus to develop. It being an election year, that didn't happen.

Still, the governor and the legislature did manage to agree on a $125-million college, prison, port, mental health and park bond issue to be submitted to the voters in November - a move that should have been made long alo. Also, the $7.4-million biennial budget - which had been short by about $220 million because revenues were consistently overestimated - did get balanced without a tax increase. But the relief is temporary, for that balance relied on one-time-only revenue measures.

For Northern Virginians, the budget does appear to pledge continuing state aid to construction of the Metrorail system. But the $10-million appropriation for this is tied to state approval of a new Metro financing plan that's not expected until next year. In other words, Gov. Godwin is still free to dump the matter in the lap of the next governor. At least he has indicated that the appropriation is a possiblity. The assembly's rejection of a proposal permitting a regional gasoline tax to help finance Metro failed, however, largely because of the inability of Northern Virginians in the assembly to agree among themselves on a measure.

The failure of the assembly of enact a bill exchange annexation immunity for suburban aid to cities also means that the financial problems of urban area will keep on haunting the next assembly session. On the positive side, memebers of the Northern Virginia delegation were responsible for some steps forward in consumer protection, openness in government, health care cost control, land use control and treament or juveniles under state care.

All things considered, then, the results in this short-session year could have been worse. Except for one slap-happy day when a committee killed further consideration of constitutional amendments long ago ratified by other states, there wasn't one of those mad, eleventh-hour scrambles in which bad legislation is made still worse before it is enacted amid utter confusion. But a difficult and sensitve financial challenge remains for the assembly when it returns next year.