For photography, none of those sub $300 ones will be worth looking at, unfortunately. Invariably, the cheap ones are TN panels. TN panels have excellent response time, sometimes as quick as 2 ms, so they're good for gaming, but they have fewer bits per channel, awful color shift, and awful viewing angles. I know. I'm staring at a 224" TN panel right now...
The
Dell 2408 is widely considered to be the best quality/price ratio on the market. It's a VA panel (MVA/HVA are the types), which means the response time is a bit slower, but the color and viewing angles are significantly better. It will run you about $600, but believe me, it's worth the extra money. I love my monitor for gaming, but as soon as I'm doing
anything else, I wish I had spent the extra cash.
The highest end monitors are IPS panels (Most commonly S-IPS), and have easily the best color representation, grayscale performance, and viewing angles, but will be around $1000 in that size, and unless you absolutely need the highest level monitor, VA panels will get it done. I believe all the Apple Cinema displays are S-IPS panels, but they are also very, very expensive.
Edit: I'll be damned... 22" Dell Ultrasharp with an IPS panel for $300...better check some reviews, though...
Dell : Dell UltraSharp 2209WA 22-inch Black Widescreen Flat Panel Monitor : Displays : Home & Home Office
Last thing's last: LED lit monitors are coming to the market now, and are in general a real improvement on the common fluorescent models that saturate the market. The light is generally more even, more white, and does not fade over time, and has a very long lifespan.
...Can you tell I'm thinking about replacing my monitor?
EDIT2: OK, I looked up the reviews for that IPS, and it seems pretty much an exact match for the 2408, despite being an IPS. Not to say it's bad, just that both monitors are quite excellent.