I recently did this exact same thing. I installed an SSD in my computer and upgraded from Vista to Windows 7. In my case, I installed the SSD side-by-side with the regular drive. I then used Ghost to copy the contents to the new SSD drive. I changed the BIOS to boot the new drive and I was done with the SSD install. I then performed an upgrade to Windows 7 on the SSD drive.
It has been really handy having the original drive in the same computer. I've been slowly cleaning out the old drive as I get comfortable with the Windows 7 install. So far, I haven't had any major issues. Another developer, however, upgraded from XP to Windows 7 and she's had more trouble. Her biggest issue has been with old XP drivers that are not compatible with Windows 7.
I wouldn't worry too much about the SSD fatigue. We've been running SSD for about a year in a number of computers and they have survived just fine. We've had multiple OS installs and at least one XP to Windows 7 upgrade.
If you don't have Ghost, Clonezilla is a great alternative. I've used it at home and work. It's not quite as simple as Ghost for straight NTFS partitions, but it's not bad either. There's a live CD that puts all the tools in one place that makes it pretty easy.