Some excellent advice has been offered thus far, all I can really do is say "yeah, do what he/she recommends." When I was shopping for my first pistol, I was pointed to this website:
http://civic.bev.net/shawnee/gunbuyer.html
It's an excellent discussion of caliber selection, revolver vs. autoloader, etc. geared toward the newbie looking for a defensive weapon. It sounds like you're also considering target competition application. The natural choice would be a 1911 -- so many options for customization now and down the line your head might explode.
Here's what I did: Sig P228 in 9mm and 1000 rounds of cheap ball ammo. Got a pretty good handle on the DA/SA trigger of the Sig, and got to be a pretty fair "combat accurate" shooter. Even 9mm adds up after a while, so I picked up a Ruger MKII .22 pistol -- just the basic, blued model to go with my basic 10/22. You want cheap to feed? .22 is where it's at, baby. Wally World sells 550 rounds of bulk packed Federal hollow points for less than $10! The terminal ballistics of the 9mm are debated over and over, but no one really questions the effectiveness of the revered .45 ACP. So I recently added a Sig P220 to the stable.
So here's my advice (to echo many others both wiser and more experienced than me):
(1) Decide between an autoloader and a revolver. (I assume you've done this, as you did post in the Semiauto Forum...)
(2) Pick a caliber: 9mm, .40 S&W, .45 ACP are generally most readily available in a variety of loadings.
(3) Select a few "candidates" from the advice on TFL.
(4a) Go to a gun show and drool, but do not buy unless the price is absurdly low.
OR (even better, IMHO)
(4b) Rent as many of your candidates as possible and give them a test drive.
(5) Buy the one that fits your hand best, points most naturally, and is comfortable to shoot.
Good luck in making your decision, and be sure to let us know what you end up getting! And get a .22...
Cheers,
MK9