After being monogamous for a while it’s now a ménage a Tréo for me with the 650 and the LifeDrive. I guess I could do it all on the Tréo, but what’s not to like about streaming and browsing in bed with WiFi and keeping a couple of full length movies on your PDA.
I also find that in meetings if you are using the stylus on the LD people assume you are making notes, but if you are using the thumboard on the 650 people think you are just fiddling with your phone (or texting your mistress or something). The fact that in both cases I’m probably playing Zuma is nothing to do with it.
If you don't mind carrying two units around, by all means, carry two units around. I like 'em for different reasons too so I will continue to carry both...at least until I can find a THIRD thing to carry around!!!