Hi,

I would be looking at a Canon 55 - 250mm as a good starter lens. This gets very good reviews and the performance is really good. It also has Image Stabilisation which can be god send. My wife uses one on her 400d and the pictures are outstanding. Theya re reasonably proced at £160 new as well.

That way you can then decide on what other focal lengths you want and wether to go for prime or zoom lens.

Jeff