Its depends on your environment and usage.
45W is a bit high, but if you are in an air-conditioned room with a well ventilated case, a 120mm-size tower cooler could do the trick, albeit with not so ideal temps.
But why would you want that though? Slap a quiet fan (Like something from Scythe) and you'll barely notice.
What I was thinking was - Some sort of copper heat sink on the CPU (with a lot of fins), and an indepedent 10-12dB fan on an adjustable bracket blowing air on the CPU heatsink and motherboard. I've heard about the Scythe coolers too, I'll take a look at them