I'm actually in the process of reviewing some wireless N routers for a roundup I plan to write. While the improved antennas of wireless N may allow more range, the major advantage is higher speeds at the same distance. So although they won't allow you to get much farther from the router, your speeds at the same distance will be much greater. They're also far less affected by walls, floors and other obstacles. My laptop will work half a block away with a wireless N connection, and speeds in the house are much greater. I'd say it's worth the upgrade. Especially, if you have Vista, VoIP, Skype, play online games, etc. The ease in setup and quality of service improvements are worth the upgrade alone.
I've never been a big fan of Trendnet, in fact I always thought of them as cheap (not inexpensive). However, I'm currently running their TEW-633GR
, and I gotta say I'm impressed. Currently $99 at NewEgg
P.S. If your notebook has a/b/g wireless chances are it already supports, or will support N. Check the mfgs site for updated wireless drivers.