I have Windows Home Premium and it does all that I want, so for me the answer would be "no". But if you particularly need any of the features of Professional then only you can decide what that is worth.
Ah - well have a look here. Are any of those features worth $30 to you? Do you want to join a Windows domain, or encrypt your file system? I suspect for most home users the answer is "no". It might just be worth it for XP Mode if you have any programs that won't run on Windows 7 - I haven't found any yet.