You don't say what type of photography you're interested in so it's difficult to be specific. However, as you've spent over £1,000 on a camera body it's worth spending some serious money on the lens(es) - go for the Canon L-series glass and you won't go wrong.
If you want one general lens then the 24-105mm f/4 is a good starting point (this is USM and Image Stabilised (IS)); the 24-70mm f2.8 USM is supposedly sharper but is not Image Stabilised.
If you want a longer zoom then the 70-200 f/4 is excellent (this is USM but the "basic version" is not Image Stabilised). Finally the 17-40mm f/4 USM is a good wide-angle lens.
I've not used any but a number of people recommend the more expensive Sigma lenses as a good alternative. Final point: remember to budget for a good UV Filter to protect your investment.
In addition to the points made by N.Tyler (below), I would recommend a fixed lens - either the 28mm/f2.8 Canon or the Sigma EX 30mm/f1.4, both of which equate to roughly 50mm in a 35mm format. I have a 7D, with a couple of Canon Zooms covering most everyday requirements, but a top quality fixed lens is desirable, especially for indoor shots without flash. I have the Sigma 30mm which is superb, and my son has the Canon 28mm which also gives superb results - but for me the extra speed of the Sigma is worth the extra money.
If you only want to have one lens, then you'd better buy the EF-S 18-200mm f3.5-5.6 IS. When you start buying L lenses then there is not really one single lens that covers the whole range. You will find yourself using it at 18mm as well as 200mm so I would definitely go for that one. However, once you become accustomed to the 7D I am sure you will want to upgrade to L lenses, and probably find yourself buying a 17-40mm, 24-105mm and 70-200mm f4. The 24-105mm is often sold as a kit lens with the 5D MkII and is a great lens for travelling and all round shooting.
I have a 7D 50mm f1.4 24-105 L 70-200 f4 L 100 mm L series macro f2.8
the 24-105 seems most of the use the 50mm and 100mm I use for portraits and the 100mm is a great 1:1 macro lens but, I do have soft focus filter to be kind as it is very sharp and unless you want to achieve brutal accuracy it can show a lot that people go to great lengths to disguise
If you really want a sigle lense 24-105 is the one I would go with 70-200 for whatever I fancy that needs a bit more reach
Totally agree, but the second lens you mention isn't the IS model - you can still get this model - I have the 70-200mm F/2.8 IS version and I love it - I never dreamed I'd get photo's as good as I do - and i'm no pro ;o)
Over many years i have had many lenses,but now have only 3 all CANON USM /EFS a 10-22mm a 18-200mm and 70-300mm that covers me for all i need .also they fit into a LOWEPRO Rezo 180aw shoulder bag with ease .Just bought the EOS 7D an up grade from the EOS 50D. M Dickinson.