As you're moving into LCDs from CRTs, the first thing to be aware of is "native resolution." LCDs have one, CRTs don't. That means you want to run your LCD at the resolution it's designed for, not something else. And most 19" LCDs are designed for 1280x1024, while most 20" and 21" LCDs are designed for 1600x1200. So, if you want 1600x1200 (and it's nice), then chances are you're going to have to spring at least for a 20" LCD.
Then there's widescreen vs. the more traditional 3:4 ratio. 24" monitors are mostly, if not exclusively, widescreen. In and of itself that's not necessarily good or bad, it's just a matter of preference. But, and this is an important but, many widescreen LCDs, including most if not all moderately priced 24" screens, have some problems with maintaining consistency in brightness across their entire width, because you have a different viewing angle way over there on the side than you do the part right in front of you. This means the colors or brightness of a given point on the screen may change somewhat as you move your head.
It's all a tradeoff... bigger, better, more expensive. You want good, big, cheap? Pick two (maybe).
FWIW, NEC has two new widescreen models coming out this month that should be very good, and at reasonable price points (i.e., under $2k) — the 2490wuxi and 2690wuxi. The latter is spec'd to cover 92% of the Adobe RGB color space. Most other monitors cover something down around 75%.
Nill
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