I love that the Aspire One runs Windows XP. The last netbook I tested, the HP Mini 2133, came with Vista, and it was slower than a snail on a turtle's back. You can also get the Aspire with the Linux-powered Linpus Lite, but that option saves you a mere $20, so why bother?
Speaking of price, Acer just knocked the XP-equipped Aspire One down to $349 -- a pretty good deal considering its 1.6GHz Intel Atom processor, 8.9-inch screen, and 120GB hard drive. I always mocked the prices of first-gen netbooks, which were at least as high as some full-fledged notebooks, but $349 is a deal, plain and simple.
Despite the low price, the Aspire feels extremely solid and durable, not cheap or plasticky like you'd expect. I particularly love the midnight-blue lid, though it sucks up fingerprints faster than Sherlock Holmes at the morgue.
To make the Aspire my own (at least until Acer wants it back), I installed Firefox, Foxmarks (to sync up my bookmarks and passwords), FolderShare (to sync my documents), and, after careful consideration, Lotus Symphony. I chose that over OpenOffice mostly because the latter is overkill for my needs. Even so, I'll be honest: I miss Word 2003.
Check out some other netbook-related posts, including Guy Vs. Guy: The Net Value of Netbooks, Turn Your Netbook Into a Kindle, and Six Ways to Make Your Netbook More Like a Notebook.