I'm thinking of buliding a PC for my girlfriend for her birthday (yes, I'm really THAT romantic), and I want to use the girly In-Win Diva mini-itx (http://www.techwarelabs.com/inwin-diva-mitx-case/) Pink case for it. Considering the limited space of this sff-case and the 160W PSU bundled with it, I have to be careful when picking out the components and I'm therefore looking for help and advice!
My girfriend is a graphical designer by trade, and she's currently studying webdesign as well, so the PC will mainly be used for image-editing, some light Flash-work etc, mostly with Adobe CS. She doesn't play ANY games at all, so there's no need to factor that in.
The 160W PSU should be enough for any system with system with IGP and a CPU rated at 95W TDP and below. This gives you room for even a quad-core system. The problem I'd be worrying about is the heat inside the case. I have a 80W mini-ITX system in a really tiny case that's running at 75 C, without any case fans. If I'm doing a system-intensive task, I tend to remove the case cover, and place an electric fan next to the case. This isn't so much to prevent overheating but let the CPU run full speed without being throttled by the CPU's built-in thermal protection.