I have Nod32 on my home computer and love it, they also make a mobile version.
One of the benifits of Nod32 for your home computer is that it is programed in assembly, making it easy on resources. I usually hate AV programs because they bog the computer down, ESET Nod32 has been running on my computer and I dont even notice it. I imagine the same is true of the mobile version.
The mobile version has a free trail, might be worth a shot.
http://www.eset.com/products/mobileantivirus.php
Please post back if you try it, I think many would like to find a low impact AV for their phones.
BTW, it says its 400k installed, and uses about 1meg when scanning. The purchase price of $38 for 2 years isnt too bad either.