Originally Posted by Julian
Don't fall for the Ryanair nonsense. They have appalling service, and dump you in airports miles from the place you actually want to go to (eg Frankfurt Hahn, 45 miles from Frankfurt in the middle of nowhere). You can get great deals on normal professional airlines (and get miles) without having to use Ryanair, which is often more expensive. If you want to disregard this advice, check out flybudget.com for more info about budget airlines and where they fly.
I second this advice
BA have quite good fares going to decent european airports, particularly from Gatwick.
Easyjet are probably the best low cost airline, they have rigid rules which they always apply on photo i.d and check in times. They do apply these rules consistently, so you know where you stand.
Gatwick is more accessible than Stansted as you have a 24 hour train service.
If you are going to Paris or Brussells, consider the Eurostar train.
Enjoy London!