The most enthusiastic buyers of ultraportable laptops are those who travel on a whim, whether for leisure or business. The Sony VAIO VGN-TXN15P ($2,299 list) should be especially appealing to these travelers because it doesn't break the 3-pound barrier. This is not uncommon for ultraportables, but what sets the TXN15P apart from the rest is a built-in optical drive, unheard of in previous systems of below 3 pounds. But before you succumb to the design appeal, you'll have to come to terms with several productivity roadblocks: Windows Vista Business requirements can be unforgiving; you'll need to upgrade the RAM to offset the extremely low-powered processor; and you'll need to get used to typing on a smaller keyboard (90 percent).