I have a Dell 2408WFP A01 and love it. It's been replaced by the U2410 though, which is all around a better panel if you really want top image quality. Otherwise, you can probably pick up the latest (A02) revision 2408 for ~$420-450 if you wait for a sale on Dell's website.
It is difficult to gauge how long electronics will last.
Back in 2002 I spent about $650 on a Planar PX191 (roughly $800 today), great monitor. Still works today, but I recently gave it away.
Generally speaking, the more expensive something is, the more likely higher quality parts will be used. Thus, potentially longer lasting life. I expect my current NEC and Planar monitors (see sig.) to last me at least another 4 - 6 years.
i think i'm gonna go for the U2410... looks beautiful, only downside is blacks lack depth, but im no pro photographer (yet) so it seems to be best bangforthebuck out there atm... $550 free shipping from dell.com ($630CDN)