I'm a fanatic when it comes to keyboards. I'm just not happy unless my keyboard has the right feel and layout. Trouble is, what's right for me may not be right for someone else. Choosing a keyboard is a very subjective process.

It's also an important decision. It's common for users to enter several thousand keystrokes per hour. A poorly designed keyboard can slow you down, increase your mistakes and tire you very quickly.

The next time you buy or upgrade a personal computer, don't just take whatever keyboard comes with the system. Try several keyboards before you buy and, if you don't like the one that comes with the machine, ask the sales representative to substitute one you do like. Most PCs now come with standard jacks that will accommodate any of the after-market keyboards. Most important: Don't buy a keyboard strictly on my recommendation or any one else's recommendation.

When it comes to feel, IBM keyboards are my favorite. Every time you press a key on a genuine IBM keyboard, you hear a "click" and get some reassuring "tactile feedback" from the switch just under the key cap. Other companies have come close to duplicating that feel, but no one does it like IBM.

Despite the great feel, I don't use an IBM keyboard because I don't like the layout. Once again, it's a subjective opinion, but I'm not fond of where IBM put the control key. I've been using PCs since they first came out and am used to having the control key just to the left of the "A" where it was on the original IBM PC. IBM now puts it on the bottom row.

Compaq makes great computers, but I hate the mushy feel of its keyboards. What's more, Compaq, like most computer companies, plays follow-the-leader so its keyboards have the same layout as IBM's. I have the same complaint about most other PC compatibles.

Fortunately, there are some good after-market keyboards. DataDesk International, of Chatsworth, Calif., and Northgate Computer Systems of Plymouth, Minn., make excellent keyboards. Neither has quite the same feel and sound as IBM keyboards, but they're close.

The Northgate OmniKey Ultra comes with two sets of function keys. One set is located on the left just as it was on the early IBM PC. Another set is above the number keys, where IBM and most other companies now place the keys. The keys on the left work like regular function keys. The ones on top normally perform like a shift-function key. They can be reprogrammed to perform like regular function keys, a control-function key or alt-function key.

The keyboard allows you to switch the positions of the control and caps-lock keys, which places them in the position where they were on the original IBM PC.

The keyboard also offers what Northgate calls "a limited dexterity mode" for users who are unable to press two keys at the same time. Instead of having to press the "A" letter key and the control, alt or shift keys at the same time, they can get the same result by pressing them sequentially.

I like the Northgate keyboard, but my favorite is the SwitchBoard from DataDesk International. I have one SwitchBoard connected to my IBM compatible and another on my Apple Macintosh. That makes it a lot easier to switch back and forth between the machines.

The SwitchBoard is designed so that you can add, remove or move modules to suit your individual needs.

The basic keyboard, which looks much like the standard IBM model, comes with three sections. Standard letter and number keys are on the left, the cursor controls are in the middle and the numerical keypad is on the far right. But these sections can be repositioned or you can add or substitute sections.

The company offers an optional trackball for $149.95. A set of 15 vertical function keys ($49.95) will be available later this month and a module with a set of 24 programmable function keys will be out by the end of the year, according to DataDesk President Robert Solomon.

The SwitchBoard has a suggested retail price of $249, but can be purchased for $159 from PC Connection, 800-243-8088, and other discount outlets. Northgate's OmniKey Ultra has a suggested price of $149 but is available for $99 from Access Computer Technologies, 800-359-6800.

Northgate can be reached at 1-800-548-1993. DataDesk can be reached at 1-800-328-2337 or 818-998-4200.

Readers' comments are welcomed, but the author cannot respond individually to letters. Write to Lawrence J. Magid, 3235 Kifer Rd., Suite 100, Santa Clara, Calif. 95051, or contact the L. Magid account on the MCI electronic mail system.