MX-3 is significantly better than Arctic silver 5, MX-2 and the Noctua paste are the easiest to spread, MX-3 is supposed to be a bit better, but harder to spread. I got the Noctua paste when I got mem a bit ago and it was very easy to apply.
For reference with a IFX14, noctua paste I recently got a 555Be, unlocked two cores, whacked it to 4Ghz while overvolted and it doesn't break 50C under load with a silent fan on the sink, which while very good isn't the best out there. At stock I wasn't going above about 42-43c load.
As for cleaner, go to your local chemist, ask for a bottle of isopropyl alcohol for cleaning electronics, they always bung me a huge bottle for 50p, add to a box of cotton buds and you'll have enough stuff to clean 100's of CPU's for years for a quid.