Bailey - you'll see 90% of the stuff to and from North America, and most of the Easyjet, BA, and Ryanair flights - there are an awful lot of them! You'll also see BMI and BMIBaby Airbuses, but you won't get the FlyBE flights (Dash-8's and Embraer jets), because theyre not ADS-B equipped.
Sometimes, you can work things out, though - for example a few days ago I binoculared (is that a word?) a C-17 - being military they don't broadcast position - but there was only one on my live list at the time, so it had to be that one.
It's all great fun!
Rod