I have been running Win 7 builds since last October and I have to say I haven’t booted in my other partitions since that time (earlier I used to boot into OSX on one of my laptops, and to other assorted server OS partitions on my other machines). 7 is super easy to install (and fast too!) but for convenience nothing beats installing it by booting from a fast USB drive.
Here are the instructions to create such a USB drive:
1. Open CMD.exe (in vista – open it as administrator)
2. Type diskpart
3. Type listdisk
4. Type select disk # (# of your flash drive)
5. Type clean, create partition primary, select partition 1, active, format FS=FAT32 (or NTFS), assign, exit
6. Extract (or mount) the downloaded iso and copy the extracted contents to the flash drive. Setup.exe should be at the root of the drive.
7. Boot from the flash drive.
Long has a tutorial here as well.