Some are saying the Samsung TN 22", the... 226bw or something is moving TN panels forward. TN is really the only panel that has a lot of innovation and advancements going still. In a low cost sense.
IPS panels come in more flavors than S-IPS. H-IPS, A-IPS, etc. Which are really the standard for image quality. Accurate color, superb viewing angles, and the blacks are getting better (this was an issue for awhile). The Apple displays are IPS and all 30" displays the rest take some research.
PVA, MVA, (VA panels) give great angles, accurate color but not as robust as IPS, this is changing though. The blacks are fantastic however. Don't let contrast ratio fool you (3000:1 dynamic, etc), the backlight is still the Achilles heel for blacks on LCDs. LED and other tech are much better at blacks.
TN, *-IPS, and *VA panels are the ones you will see today. Some pros swear by IPS and ACDs. However, other panel techs have come far and exceed or match IPS. Namely MVA panels.
Eizo uses *VA panels in their "lower" end LCDs (still $1000+ USD). Dell uses a PVA panel in the 2407. If you want to research displays check out the hardforum.com display section. Some of the best information you can find on the net. Hands down.
http://hardforum.com/forumdisplay.php?f=78