The western side of Scotland is particularly spectacular, as are the western islands (Skye is probably the most famous - The Wicker Man was shot there).

If you do visit England, check out the Lake District as well as obvious tourist-y places like Oxford, Bath, and London. But don't bother with Stonehenge. Trust me, it's hugely overrated.

Also, if you are in England, and feel the urge to head west to Dartmoor, etc, give me a shout. I'd love to grab a beer with you. :)