definately.
I use both Windows and OS X (macs) daily.
OS X is much better than vista which was slow, buggy and used the outdated start menu/taskbar method to launch and manage windows used in XP, windows 98 and 95 etc. In OS X you have a dockbar which is much better.
However... Windows 7 I would say is much quicker, less buggy and nicer to use than OS X, and 100x better than vista. The new taskbar and aero peek is fantastic (I expect apple to be stealing this soon). Your machine will be much faster and nicer to use with 7 than vista - so yes definately go for it!
As Priest says, maybe consider a Mac, but I think windows 7 is nicer to use than OS X (esp. if you are used to windows) but macs are much nicer looking machines being made of good quality plastics and aluminiums, but are very very expensive compared to most PCs.