My Samsung Q1 is presently my bestest mate (this might change quickly, I'm very fickle). Wtih it's dinky keyboard and tiny size I keep getting it out and saying to myself "Complete PC here you know, even running XP Professional". Now I've added extra memory it will let me do just about all the things I want it to. Lovely.
I got the little case and keyboard, but carrying it around was a problem, in that I wanted a bag for it. I got one but it was not quite right, so I've gone and got a Crumpler "McBaines Baby -M" which is a perfect (if rather snug) fit.
If you've not come across Crumpler bags they are worth investigating. I got one for number one daughter over a year ago when she got her first portable computer, and it has stood up amazingly well. She now uses it as her "everything" bag, just throwing in all the stuff she needs for lectures (including the PC) before she rushes out of her room.
Crumpler bags are tough, well made and have the most amazing things written on the labels. If you are after a nice bag for your shiny UMPC you could do a lot worse.