Even XP is tight at 8GB. Some people use a tool called "Vlite" to strip out "unwanted" parts of Windows 7, but this often results in a system that doesn't work right because there's little guidance as to what you can safely remove without affecting other functions.
I suppose it all depends on what you want to do with the netbook. If you're going to use it seriously, then I'd suggest getting at least a 16GB SSD
if not larger. I went for the biggest I could get at the time, 64GB, but these are expensive.
If you're just experimenting and don't want to spend more money, then consider Linux, or the tools for stripping down a Windows install. You may be able to get significant space back by disabling hibernation, if it is enabled. If you have 2GB of RAM, you can eliminate the pagefile.