I ended up ordering a Foscam FI8918W for the low-low price of $86. It's not nearly as high quality a camera as the others I've considered, but the reviews are mostly positive, and it seems like a decent starter model.

My plan now is to place it in a window that has a decent view of my front lawn until I see a good deal on one of the more expensive outdoor cameras, at which point I'll re-purpose this one to cover the back of my house. The eight meters of infrared coverage won't be very useful, but I can always add additional IR lighting later if need be.

I'll stop back here to post some thoughts on it once I have it set up.