Stoeger Cougar 8000F. The Cougar is the best gun for the money (around $400 at Academy). The Compact Cougar will be out in April or May 2011.

I like my full size Beretta PX4 storm. I bought it for my wife's bedside gun, but I really like it. I would also look at the S&W m&p line. Great guns!

1... Beretta 92FS or Beretta 92A1

2. For concealed, I conceal my 92FS... However, if I REALLY wanted a subcompact, my #1 choice is an Hk P2000sk... But that's over your price range. IN your price range, probably an XDsc 9mm, although I really prefer DA/SA guns...

Glock 19, carries and conceals well, accurate and dependable. If it has to be full size, Glock 17.

Walther P99c or a CZ75 P-01

Beretta 92
Glock 26 or Stoeger Cougar to save a buck
Eli

I would have to stick with my PX4 storm. High capacity, handles great, very accurate, and very reliable. I CC it daily, and don't have any problems.

If I personally could have only one do all pistol from a practical perspective it would likely be the 92FS although Glock 17/19, Sig 226/228 and even the M&P9 would be worthy honorable mentions. Selection based on my ability to carry it, use it, common military and police platform and the abundance of ammo, accessories and parts (mags, springs, etc.). The 92 is a big boy but carries surprisingly well for me in a belly band. I love the HK's but supporting it can be challenging. YMMV.