Not really a sex scene, but I find the kiss in Gosford Park between Clive Owen and Kelly MacDonald pretty hot.
Also what about the love scene between Angelica and Sexby in The Devil's Whore? Tender and erotic and John Simm still looked gorgeous with the bad wig and scar.
As for tv, there is a scene in Perfect Strangers between Matthew Macfadyn and Claire Skinner that's very sexy (well, I think so anyway!)
Totally agree about Sea of Love too.