Madshrimps posted a review on the Phenom X3 8450 and compared it to the AMD X4 and Intel C2D. Here's an excerpt:

All in all, I'm surprised in a positive way with the AMD X3 triple core processor. Yes, gaming performance is a little behind, but the difference is very small, games which support multi cores will get a nice boost with the X3, unfortunately the list of games that efficiently support more than 2 cores is very short. Three cores is innovative and in fact a brilliant move from AMD, because Intel is not capable of producing triple cored CPU's as they work with native dualcores (a quadcore = 2 x dualcore glued together).

AMD Phenom X3 8450
+ Pricing
+ An extra core in comparison to the 45nm Wolfdale
+ Performance/Price Ratio
- Gaming performance lower than expected
- Locked multiplier doesn't make it very overclocking friendly
- Low base frequency of only 2.1Ghz

Being a hardware enthusiast and overclocker, I'm not in favor of AMD's Phenom series, because the overclockability is too low, HOWEVER, if people ask me for a well-priced configuration that can play the latest games fluently and has no issues handling video encoding instructions, I will recommend to at least consider buying a Phenom. The motherboards are quite affordable, the processors are actually cheap, the performance is good.

In the end, I have to admit that AMD's X3 move was clever and definitely should be seen by Intel as a worthy competitor for their Wolfdale series in regard of price/performance value.