I'm currently in the market for one myself. Got a birthday coming up and put it on the list for my wife to get me. I've always wanted one with a rain gauge and anemometer.
My primary requirement is that it must have 2 outdoor sensors. One in the usual place outside, but another inside the garage. I haven't really found anything yet though.
And I'd really like it to interface with my PC so that I can track history and whatnot.
I've been using a regular outdoor thermometer that has 3 sensors. One I omitted and kept as a spare until one of the sensors failed, then I substituted the spare. A couple weeks ago, the "head unit" inside the house failed as well, so it's time for something new.
The units I've been using have only lasted 2-3 years at most. The current one is just 2 years old.