My three current favorites / tips among LCDs (I assume you're not interested in CRTs):
A. ViewSonic VX 922/924 (TN panel, 19", 2/3 ms gtg)
+ good price
+ extremely fast, virtually no ghosting
+ crisp, vibrant colors
+ nice design
- poor viewing angles (especially vertical)
- 6-bit color
- subpar video playback
- lack of height adjustment, pivot, swivel
- 5:4 "square'ish" aspect ratio
- large pixels (grainy image, screen door effect)
- blacks not as deep as on VA panels
Conclusion: a good, affordable monitor if fast gaming is your top priority and you don't care much about anything else.
B. ViewSonic VP2030b (P-MVA panel, 20", 8 ms gtg)
+ fast panel, good even for fast games
+ good viewing angles
+ good, 8-bit color
+ deep blacks
+ good for videos
+ small pixels and lots of real estate @ 20"
+ tilt, swivel, pivot, height adjustment
- may be prone to backlight problems like its smaller brother VP930b
- large footprint
- colors not as good as on S-PVA new panels (e.g. on Samsung 970p)
- not as fast as quickest TN panels
- requires a potent video card for serious gaming
- aging design
Conclusion: maybe the best gaming/allround non-widescreen monitor available.
C. Samsung 244t (S-PVA panel, 24" widescreen, 6 ms gtg)
+ very fast panel, IMHO better than P-MVA, almost zero ghosting
+ very good viewing angles
+ great, 8-bit color
+ deep blacks
+ good for videos
+ widescreen = pure bliss in some games
+ tilt, swivel, pivot, height adjustment
+ good design
+ HDCP support (not confirmed 100%)
- widescreen support still weak on the whole
- pricy
- potentially some pixel crawl in movies
- requires an even more powerful GPU to run games in high settings @ native res
Conclusion: not cheap but possibly the best LCD monitor on the market, IMHO thanks to its panel, clearly eclipsing the popular Dell 2405FPW.
My own recommendation: many gamers favor fast TN displays because of their reaction time. Even though I'm a gamer as well, I do not. 8 ms P-MVA and 6 ms S-PVA panels are really close in terms of ghosting behavior but offer much better viewing angles, colors, image quality in general.
Other good options available now: Dell 2405FPW (12 ms PVA), Eizo S2410W (8 ms MVA), Samsung 214t (8 ms PVA), Samsung 204b (5 ms TN), Samsung 970p (6 ms PVA), ViewSonic VP930b (8 ms MVA), ViewSonic VP2130b (8 ms PVA)... There are a few decent NECs, BenQs or Belineas as well. Samsung 930bf (4 ms TN) is also popular but some heavy artifacting was reported by one of the most credible review sites so check it out before buying.