It's a good deal on the Compaq ones, especially the 3765, since it works out to be $349 after rebate, before tax. I upgraded by 3635 to a 3765 - the extra memory is very nice.
The $50 off the 3800 series makes it a decent deal as well, mostly because dell.com doesn't sell Ipaqs. If you want around, you can probably use the dell website to get a better deal on the HP's though.
Overall, a very good deal on the 3765 !