This deal has ended.
Buy.com has the 4gb Sandisk Cruzer Micro Titanium USB Drive with "ReadyBoost" for $31.99 after a $40 mail-in rebate valid through 6/24. Shipping is free and there is no sales tax (except CA, MA, MD, TN). New customers can use this $5 off $50 coupon and new Google Checkout users can get a $10 off discount for signing up (but you can't get both). A bit on readyboost: it "allows your PC to use any flash drive enhanced for ReadyBoost as additional memory, making the flash drive an extension of your system's RAM. Because applications can be retrieve data from the flash drive more quickly than from the PC's hard drive, your system responds faster and runs more efficiently."