Without starting another idiotic AMD-vs-Intel thread...
The original marketing attempt from AMD was to put a number at the end of the series model that buyers could associate to the pompus Intel speeds being splattered everywhere at the time.
For instance, a 3.0Ghz Intel was comparable to a AMD 3000.
That only worked well up till the end of the AMD Athlon XP series. Now with the new 64bit AMDs and the even newer dual-core 64bit AMDs, the comparisons really diverge. It's not as simple anymore to just say that the speed of one is comparable to the speed of the other. They are functionally too different now.
Your best bet for determining what is good for you, is to read some benchmarks comparing the AMD and Intel chips you're looking at, for tasks you intend to perform. Everything else is purely unfounded conjecture.