Just go with Windows 8 unless the price points matter to you (and then you'll probably upgrade before you stop using your computer, so I'd go with W8). If you happen to get windows for free, do whatever, you're not exactly bound to an OS then; though I would still go with W8.
The only bad part about W8 is the lack of a start menu, and I don't even find that bad, it's an improvement for me, personally.
In general, if you use your start menu more than 5 times per day, I would stay with W7, because you clearly haven't found out that you can pin programs to your toolbar. That could be an issue because it's probably the best feature of W7. I use my computer > 100 hours per week (60-80 for business) and I only use my start menu less than once per day on average.