I have a $4 ultra clip vent mount and it works great if you have a case with a ultra clip tab (piel frama, vaja, etc). The thing seems like it was designed for my cars vent... it holds it in place and dosnt budge. Im never afraid of my ipaq falling, and I drive pretty hard. Another benefit is I dont even need to take my ipaq out of its case. I unclip it from my belt, and onto the vent mount

It doesnt block your A/C either... it holds the ipaq about an inch away.
for those who have trouble with the vent mount... dont clip it onto the top slot! This was my problem at first. Putting the hooks on the second platic slot thing works perfectly.
oh, and universal systems are great. My phone uses the same tabs, so when Im not carrying my ipaq I slid my phone onto the vent mount.