Welcome to the forum, blueejay.
I'm going to suggest the D5000. You say you're "looking into buying" a DSLR and not upgrading or replacing, so...
Here's why I suggest the 5000 over the 5100:
1. Price. Whether the 5100's features migrate up from the 3100 (as rumored) or down from the 7000 (not terribly likely from the looks of it), it's going to be a somewhat more expensive piece of kit. The 5000, on the other hand, is already showing up marked down in several places.
2. Price. Yes, I know I just said that. But with the money you save, you'll have more cash to lay out on lenses. At the very least, you'll probably want a longer (i.e. 55-200 or 55-300) lens to go with the 18-55 kit lens; you may also find yourself wanting the creative and practical options offered by faster glass (even if it's just a cheap fast prime, like a 35 or 50mm 1.8).
3. Timing. If you want an SLR and have the cash, get the darn camera and start shooting already. The 5100 hasn't even been announced yet, so you've got the gap between the time it's announced and the time it starts to ship (the 7000 took a little while), and perhaps even longer depending on demand before you're able to get your paws on one. The recent tragedy in Japan may or may not play a role in how long it takes to see the newer model on store shelves (Sendai manufactured higher-end stuff, but I'm not sure if any of the innards for lower-end models also came from there). The bottom line, though, is that the time you spend waiting on the newer camera could be time spent getting to know the camera that's closer at hand, and also making some great-looking photos.
Once the 5100 is announced, if you decide there's something in the ACTUAL specs (not the rumored specs floating around now) that you absolutely can't live without, then wait for it. Otherwise, get the 5000, get out there, and enjoy yourself.
Hope this helped.