i really hate it when people say,
"why dont you buy X, as you can overclock it to be the same a Y, and save money"... dont you realise that if we're including the option to overclock then we can overclock Y to be equal to Z; which will trounce X
In short the FX-55 overclocks very well, and in an overclocking race will leave a 3700 for dead, period.
If your asing for a debate on wether to get the fx-55 or the X2 4400, well i could start asking about whether you plan on overclocking etc.. but to be honest the 4400 is a good ocer at a considerably less cost and is the clear choice
personally i would go with the fx processor.
why
As for the debate on whether to wait for M2, well you can always argue to wait, new technology is always coming up. Intel have a great roadmap for 06, and although amd are moving to M2 you're not going to see huge archetecutrual changes other support of ddr2, straight away. Entry level of x2 on M2 is going to be the X2 4800 (i think) so you could be looking at q3-q4 before AMD start making cheaper X2 chips for the M2. If you can wait untill autumn then fine do so, at least that way you'll see the new cornroe/woodcrest benchies.
But if you cant wait that long the X2 is the clear choice here.