Boy, there are alot of opinions flying around for Intel vs. Amd...
Ok, I'll tell you what I believe about both platforms. Others may disagree, but that's OK. (just don't listen to them!)
--AMD-- Pros:
Best bang for the buck.
Higher Floating-Point operations.(programs such as Adobe Photoshop and Adobe Premiere will run quite a bit quicker than running on Intel P4) As well as most programs will run just as good, if not better on an AMD then a P4. (IMO from experience)
They will last longer as far as upgrading goes. AMD tends to stick with their original design longer than Intel.(i.e. socket A has been around for a LONG time, while Intel can't figure out which socket and RAM it wants to stick with.)
Cheaper(for the most part).
There are some CPU versions that O/C extremely well. Most others will still give you a decent O/C.
Cons:
Quite expensive in the couple newest additions to the XP family.
They tend to run a little warmer than P4s.
Don't have quite as much cache as the P4s.
--Intel-- Pros:
Their Price vs. Performance is getting better.
Newest revisions have Hyper-Threading support. (some say it works, others say it doesn't)
Has a heat spreader on the CPU to help a little more with heat dissapation.
Runs a little cooler then an AMD. Thus is able to acheive higher O/C's with stock or non-high-performance cooling.
Cons:
Very Expensive for the latest CPUs.
Poor performance with DDR(compared to AMD) and RDRAM while faster, is harder to find, more expensive, and not many chipsets will support it.
May stop letting you O/C your CPU.
Switches platforms more often than AMD. (thus requiring you to upgrade more than just the CPU)
Well, this is the situation as I see it.
I have always liked AMD, and believe that definately there is a better 'Bang-for-the-Buck' in Athlons. And, have noticed at least(mostly better) same performance as the Intel for less $$.
Since you're talking about Athlon 3000+ exclusively against Intel 3.06Ghz, it could be a draw deoending on what you will be doing. Give us some examples so we can better help you.
David