I have a Latitude 400 model (an earlier version with a 650 processor} which is flawless, THe 600's are good also I hear, but Id onot have first hand usage on them. The 610 are swerr but have the integrated Intel graphics as opposed to a discrete chip, so maybe yes, maybe no on problems with that. Dell is deeoply entrenched with Microsoft. Don't forget that.
I will boot my son's school's 610 up this weekend with a Linux Live CD and check on full compatibility, if you like.
Wireless cards are still problems with Linux as tha makers do NOT release the uinfo on the chip sets and they change the actual chips within the same model without telling anyone (even the consumer), The universal card for me in the Kinksys B card, rev 3. (Version 2 and 4 don't work, yet.) The version 3 works with everything I have tried.