This one. Use coupon code TP2GK4X1DTX0C8 (expires June 3) during check out. It comes out $229 + tax (after $50 mail-in rebate). Slightly cheaper than Amazon ($290 after $50 main-in rebate). Dell also offers Nokia N85 at $247 + tax (with $50 main-in rebate).
(Update May 25) The offer expired on late night May 22 when I was comparing N85 with Nokia 5800. However, one can find lightly used ones at eBay for about $230 to $250.
Found this Nokia N85 Reviews from theNokiaBlog: Nokia N85 Review – Part 1 The Physical; Top 5 Reasons Why Nokia N85 Is Better Than Nokia N96; Nokia N85 After 3 months – Build Quality Results (video below).
(Original May 22) Saw it from dealsea, here is the %15 off stackable coupon at Dell Small Business: