I'm personally between the Umid M1, Nokia N900, and Sharp PC-Z1 also.
They all have features I'd like, but still no one clear 'winner'. Waiting on more hands on reviews, and of course price may decide for me. Right now, for a 'pocket' device, the N900 is looking good ... but the draw of a smaller ubuntu machine makes me think twice.
I currently still shuffle between a EEEPC 900HA, Nokia N810, and *cough* Ipod Touch *cough*. My Z has been shelved for about a year