I don't think that Intel is really the best---I need something to handle a large workload and some and have heard that AMD is better at handling large workloads.....
You heard wrong. Intel currently produces the "best" processors, especially in the high-end range. Anyways, to stay on the topic of the question, try a Phenom II x4 955, 965, or 970. If you feel that four cores wont be enough for the tasks you have in mind, you can try a hex-core (1055t, 1075t, 1100t etc). You could also probably find a cheap yet capable board that'll work with these.
Lib is correct, the Phenom x6 1100t is the current flagship. That being said however, it gets outperformed by the i5 2500k. Also, after just seeing the prices for the bulldozer chips, apparently you will be able to purchase an Octo-Core clocked in at 3.6 GHz (with a turbo-boost feature that moves it up to 4.2 GHz) for around the same price you purchase the i5 2500k. However, bench marks aren't out, and I'm 98% sure Ivy Bridge/Sandy Bridge-E will still top out Bulldozer. The core architecture sounds strange though. Anandtech said its somewhere between hyperthreading (so that 1 core has two threads, 2 cores have 4 threads) and a traditional multi-core processor
Well, just because you don't think Intel is the best doesn't make that true. Intel consistently outperforms AMD and is better at handling large workloads. There is a 6-core AMD processor that is worth looking at though, but if you want performance, you should look at Intel i7.
Until Bulldozer comes out, the X6 1100 T is their best CPU. Still inferior to most Intel i7s
