I can imagine an ugly Tolkien/D&D elf without much trouble, but, yeah, an attractive Tolkien/D&D orc is a bit tougher to picture.
For the elf, just imagine any ugly human and add pointy ears. You can't tell me Hugo Weaving (Elrond in the LotR movies) is really all that good looking. ;) Average at best, unattractive at worst.
As pointed out with the elf, he may not have been born ugly; battle scars and what not could have changed his appearance. Burns to the face come to mind.
Biologically, I don't think the orc has much chance of being Attractive, but Google image search came up with a few
examples (mainly of females or half-orcs)...