i always recommend rats as i find they are much more interesting and interact with you alot more. I currently have 10! the girls DO smell better than the boys, although i'm planning on litter training them shortly. I would also not recommend wood in the cage. Not just because of the smell but we've had shavings before and it had lice in it!!!
we currently use a paper pellet bedding called bio-catolet..it doesn't smell and its easy to clean, and once the rats are litter tray trained, completely recyclable! even put it in your compost bin!