I moved from XP Pro to W7 Ultimate about 3 months ago. No problems other than getting familiar with the new "look & feel". I can still run some elderly hardware (including a scanner that used to run under Windows NT) but I don't think that's possible with any version of W7 other than Ultimate.
And I managed to save quite a lot of cash by using
this software supplier and quoting my Open University student number (no connection with the firm other than as a satisfied customer)