Very nice! I was always into nature photography but I did a bit of everything really, definitely want to get a better kit so my images are a better standard!
I have a few pics up here:
http://www.lindsaywilsonphoto.co.nr (just a quick portfolio I made for my CV)
The Nikon D3100 is a nice camera, I'm using my Sony A380 DSLR with 50mm 1.8, 70-300mm 4-5.6 and 18-55mm 3.5-5.6 lenses for years, but the last 2 are cheap glass therefore chromatic aberration occurs quite a bit and they just aren't hitting the standards I need now.
However, I'm hoping to upgrade to a Canon 60D or 7D soon, but I'm having to wait it out at the moment as they're due to release replacements for those 2 so I'll see if the replacements are worth the extra money/buy one of those cameras at a reduced rate. I'm hoping to get a 35mm 1.8/1.4 lens as a basic walkabout lens with the camera instead of the kit lens in the box, then a 70-200mm f/4 zoom (cannot simply afford the f/2.8, well over a grand!) in a few months time, but as I said, having to wait until Canon finally release something before I can splurge (I also don't have the money at the moment, whoops!)
Unfortunately I can't really consider Nikon (I'd get a D7000 if I could) because their pro lenses are even more extortionate than Canon. It's a shame though, that camera is beautiful, but I wouldn't be able to afford anything I want to shoot with!