That's a lot of questions! I'll try to help with what I can.
1) I am planning on using a Wells Gardner d9200 Monitor with the ArcadeVGA Card from Ultimarc. Good choice is this the right way to go?
I don't have any experience with these. Sorry.
2) I plan on having 4 8way Joysticks, 1 4way Joystick, 1 2 1/4" Trackball (Thinking of two), A Tron Joystic, and Tron Spinner all on the control Panel. I figured on using the I-PAC/Opti-PAC combo of boards from Ultimarc. Will This handle all of this? and again is this the right way to go for this configuration?
Wow! That's going to be a big CP! I would think about what kind of games you are really going to be playing the most. Build a comfortable panel for those games. If you really want controls for every game you can think of, you may want to look into removable panels or a rotating design like 1up's. By the way, if you are reading this 1up, great job on the cab!

3) With the configuration Listed above, Will light guns work with a d9200 monitor/ArcadeVGA Monitor? If so, Which Light Gun is recommended?
Act Labs guns are you only real option. The VGA guns I have heard will work with arcade monitors. That's just what I've hear. Don't quote me on that.

You could also hack some T2 guns (once again, see 1up's cab

). These types of guns are basically a joystick with a gun for a handle.
4) I see some people have gotten Dragon's Lair working with these setups, some web site even say "Comes with Dragon's Lair/Space Ace files" What are these files and what would I need to get games Like Dragon's Lair to work
For laserdisc games like those you need the ROMS and MPEG files for the game you want to play. Daphne seems to be the emulator of choice (maybe the only choice). You could also get the PC game for Dragon's Lair on DVD-ROM or CD-ROM. The non PC DVD versions, I have heard, don't play well on PC.
5) Computer Set up? What is recomended... Want to be able to play all the mame arcade games well. Not really interested in booting up Medal of Honor: Allied Assault or anything like that, mainly the Classics... so what prosessor, motherboard, Operating System, Memory, HD, Etc, would you guys recomend?
This really depends on what you want to play. I run a Duron 900MHz with 256MB PC-133. I can play, I'd say, around 95% of MAME games at full speed. If you want to play KI2, Crusin' USA, War Gods, etc... you can't really buy a fast enough PC.

You OS will depend on your choice of FE. I went Win98, but DOS and Linux are also good choices. I'd stay away from NT kernel OS's (NT, 2000, XP). They don't allow direct hardware usage. This may limit some of you options.
Take some time to read through these boards, and check out the projects section. You will get more info than asking general questions here. Generally, you'll get better responses if you ask specific questions. Just an FYI. Hope this is helpfull.