Better way to validate password with regex

[wild_bill]

The password requirements are:

Must be at least 8 characters
Must include at least one number
Must be alpha-numeric

I came up with this, but it seams overly complicated for what I'm trying to do. Can anybody improve it?

"^(\d\w{7,}|\w\d\{6,}|\w{2}\d\w{5,}|\w{3}\d\w{4,}|\w{4}\d\w{3,}|\w{5}\d\w{2,}|\w{6}\d\w{1,}|\w{7}\d|\w{8}\w*\d\w*)$"

[wild_bill]

This came from a different board, looks good.

"^\w{8,}(?<=\w*\d\w*)$"