Is color accuracy very important? Or is "close enough" good enough for you?
LCD monitors using 6-bit TN panels are relatively inexpensive, but due to technology limitations, their colors are not very accurate. TN panels can only produce 256k real colors. The remaining 16.5m colors are create thru dithering where colors are "guess-timated". This leads to less than precise colors and image artifacts especially in areas where there are subtle color shifts. Another limitation of this technology is viewing angles where colors generally shifts when viewing it at angles.
More expensive monitors uses S-PVA and P-MVA panel technologies and at the highend are the various IPS panels (like S-IPS and H-IPS). These monitors can truly reproduce 16.7m colors. The really highend ones also incudes a 12-bit or 16-bit gamma internal lookup table which improves color accuracy even more. These monitors do not suffer from limited viewing angles like TN panel. There will still be color shifts, but less extreme.
There are a handful of non-TN panel 22" monitors. One is made by Lenovo called the ThinkVisions L220x with a resolution of 1920 x 1200 instead of the standard 1680 x 1050 resolution of other 22" LCD monitors. It uses a S-PVA panel and costs from $450 - $500.
I recently became aware of Eizo (well known for image quality) new 22" LCD monitors that are geared towards the "general consumer". These 22" monitors ranges between $600 - $750 which is more affordable than their highend ColorEdge C221 (I think) which ranges from $4,000 - $5,000.
As for 24" monintors, generally speaking, anything selling for less than $550 online will be using a TN panel.
I recommend the 24" NEC LCD2490WUXi w/ SpectraView. You should be able to find it for around $1200 - $1300 in the US. SpectraView is a colorimeter used to calibrate the monitor to improve color accuracy.
I have the 26" version and I like it alot. The 24" version tends to have less image quality issues than 26" version based on some user reviews I've read. I believe the LCD2490 uses a S-IPS panel instead of the H-IPS panel that the LCD2690 has. Additionally, the LCD2490 does not have wide color gamut (92%) compared to the LCD2690.
Your best option to find opinions for an appropriate LCD monitor based on your needs/requirements and budget is to go to HardForum.com. They have a very active "Display" forum community and can steer you to another monitor if the NEC I recommmended is too expensive. They should also be able to vouch for the NEC LCD2490 as well.