(1) I don't think a multi-year warranty is as important with a $300 PDA as it is for a $2000 system. You can always buy more time during your warranty period. I went with 1 year.
(2) Definitely get screen protectors. The Dell ones are fine, lots of people talk about
writeshields being the best. I bought the 3-pack stylus so I have them if I loose/break the one that came with the system. Would not be fun to have to wait for Dell to ship when I needed them.
(3) I have the cradle for synching with my desktop upstairs, an extra charging cable for downstairs, and a
cigarette lighter travel charger for my truck.
(4) I bought a second battery just in case. Mainly for long trips in my truck with the GPS CF card.
(5) Buy as big a Secure Digital and Compact Flash memory cards as you can afford. I recommend at least 256MB each.