As someone already mentioned, why look at the 830 at $266 when the 920 is $243???? And it will overclock to the sky. The X2 3800 is about $295.
Even if you wanted to get the 930 ($324), it will be getting a significant price cut next month. Though if you overclock, the 930 and the 920 will achieve similar overclock speeds, so why spend the money for higher stock clock if you are going to OC anyway? And the 920 will get a price cut next month as well, bringin it under $200.
Here's some comparisons between the 3800 and the 920.......
Tom's Hardware - Price/Performance Index
Tom's Hardware - 3DMark03 - CPU
Tom's Hardware - PC Mark 05
Tom's Hardware - CloneDVD
Tom's Hardware - Media Encoding
It's kind of a ping pong match, but all are really close either way. Plus, this is at stock speeds. The 920 will reach 4Ghz on air (Big Typhoon) rather commonly, and 4.5 on Water is not unheard of. At that speed, I have no doubt it will slam the 3800 at stock speeds. Not sure how high the 3800 can overclock, so that might be something to look at, but from my understanding, AMDs don't can as much clock speed from OC, so it might just bring it back to even.
However, in reference to price, if you are currently running an AMD, then technically it would be cheaper to get the 3800, as you would have to buy a new motherboard to use the 920 (and most likely RAM, as Intel uses DDR2 for it's high end platforms).
And vis versus, if you are already running Intel, it would be cheaper to go with the 920 as to use the 3800 you would need a new board, and as I mentioned, the 920 is already much cheaper than the 3800.
In the end, the actual choice on what you need, and what you can spend will ultimatly determine your final decision.