If Tempe's coffee-shop scene was more like that in Central Phoenix, I don't think Xtreme Bean would survive. As things are though, if you're in the area looking for a hangout spot, it's a solid choice. If you're looking looking for good coffee, go across the street to Goldbar.
I've been coming here since high school, when it used to be the hip spot to hang out. It's got a spacious, lively main area where there's often music in the evenings, with a couple quieter nooks if you want to buckle down and get some work done. They make a pretty good Italian soda, and I'm not above indulging in their chocolate cake and breakfast burritos. Baristas are usually pretty friendly, though they're sometimes more interested in their own conversations than in welcoming customers. I no longer order black coffee here, because lately it's been lukewarm nearly half the time.