Actually, for some reason I can't hear "Let's Get It On" and not laugh. I guess because it seems so cliched to me. Well, that and I still to this day have this mental image of one of my friends deciding to strip to that song, which has forever burned a very painful scar in my memory.
Well 9 times out of 10 if you can't score to that you have no business scoring. Isley Brothers are another one. I just like Janet's "Would You Mind" simply because the whole song is about sex and sex acts.