I would take a system with an AMD Phenom 8750 Tri-Core over an Intel Core 2 Duo E7300 Wolfdale system since you are getting a Tri-Core processor over a Dual-Core. They are both great processors though.
I say give your business to AMD. Keep them in business that way we get better quality processors. The competition between Advanced Micro Devices and Intel gives us better quality products.
I love my Athlon 4600 Dual-Core processor. A Phenom 8750 Tri-Core processor is a great CPU.