Windows 7 SP1 doesn’t bring nearly as much to the table as some past Windows service packs. There is almost exactly nothing to see here unless you’re running Windows Server 2008 R2 (my money says most of you aren’t), and even then it only helps you if you’re deeply invested in a Microsoft backend for your thin clients.
To install the update to your existing Windows 7 PC will generally take no less than half an hour (not including download time), and probably more on older hardware and netbooks. In daily use you won’t notice any major performance improvements, especially if you compare, say, Vista RTM to Vista SP1.
Windows 7 SP1 will get you a more secure (and possibly more stable, depending on your particular circumstances) PC, but it doesn’t change things up under the hood nearly as much as did Windows XP SP2 or Vista SP1, or even XP SP3 and Vista SP2.