It's 77F in my room, my processor is 55F and it would probably be 50 if I wasn't compressing some files. So now, It doesn't just go a few degrees below ambient. It all depends on how powerful of TEC you have, how much power you give it, and if you have enough radiator size adn CFM to remove the heat the TEC creates.
When I switched from using 2x80w pelts to 1x226w, I was able to push my processor 100mhz faster using.025 more vcore, and the temps were still lower. If I set it to what it was 100mhz ago, I get 1-2C idle temps.
As processor speed goes up, temperature needs to be lower, and voltage needs to be higher. That's the basic reality.
So anyways, I wouldn't go 64bit yet because it's not really useful, its costly, and you'll want socket 939 later anyways. I think you should stick with what you got, get your TEC setup which is the last cooler you'll ever need if you get a 226w tec. the trend of cpu development is turning to make them more energy efficient and thus mobile, not so much faster.
I personally like danger den things over Swiftech just because they use all coppper designs and I never really trusted the quick connect plugs.
So a Maze4-1 could be your answer.
But for ease of installation, the latest MCW5k what not from swiftech. Don't forget to insulate.