AFAIK, AM3 isnt going to come out anytime soon. Id give it until K8L Dual Cores come out in mid-2007. Dont wait for it if youre thinking about building a computer right now.
As for Conroe, I dont see why you shouldnt get it if its in your budget. Its true that its hard to find a lot of good motherboards for them, but you dont need a lot of good motherboards. You only need one in every budget class, and there are good ones for every budget class.
The processors themselves are great. Theyre better than what the Opteron 165 was. Anandtech just did a review of the ASUS P5B-Deluxe motherboard. It was able to reach 525Mhz FSB (while others stop at 370) and allowed a [retail, B2] E6300 to reach 3.68Ghz. That was a full 100% overclock, and higher than what a supposedly cherry-picked B1 E6700 was able to achieve.
Granted the motherboard costs $260, and the processor $193, but when you get performance that no AMD processor has ever matched, its something to think about.
I tried to answer your original question, but like Vaderpro said, the links dont work so I dont know how your budget would fit a Conroe.