id perfer alpha
ive put a alpha on my grandparents tbird 800 and 2 of my friends pcs they are sweet my grandparents i oced up to like 1 gig without watercooling and just the smaler alpha heatsink on there from www.3dfxcool.com
depends on the cpu, if it is socket a definately get a shim from here so you don't crush your cpu and get the WBK38, it is a monster cooler, and will cool very well. The Fop32-1 is pretty good, but the WBK38 is not too much more expensive and fits both socket370 and socketA. Be sure to get one of the shims in the link so you don't crush the core, globalwins have a strong clip and a history of doing this.
I have an FOP-32 and though it did a fair job, I would recommend the ThermoEngine with YS-Tech Fan, over both of your choices. The price is in the same range. I have one on loan for some experimentation and I was really impressed with its cooling ability when paired with the YS-Tech Fan off of my FOP-32. Running my 1G Tbird at 10x145 1.85V (84Watts), it kept it at 40C running Prime95 Torture. My BMF MC-462A only kept the CPU 3C cooler under the same settings.
Now, if you were considering one of the several new copper units recently reviewed on the front page here, I'd say go with any of them. Copper is almost double the thermal conductivity of aluminum. They do cost more, but they work better.
the copper ones are great, but they are heavy, and getting over the weight recomendations for the socket lugs. I am afraid one of the suckers is going come off cause a lug breaks and then I am screwed. The thermoengine looks good too, if it cools that well with the ys tech fan, i can't see why not to get it.