So I've been gradually upgrading my PC, on as tight a budget as possible. Next step is to get an SSD for Windows, and a nice big normal HDD for all my files. Before I do this, I need a new motherboard, as I only have two SATA slots right now. Thing is, I have no idea what kind of thing is good for a motherboard, so I'm looking for some recommendations.

It needs to be AMD, socket AM3+, as I'm going to use the same processor. It needs a decent amount of SATA slots, and at least two PCI-e slots, so I can SLI up my graphics card at a later date if necessary. I guess I'll grab like 8GB or so of RAM to go with it. I have a pretty big case, so size isn't really an issue, but ideally I'd like to spend as little as possible :D