For a starter gun ....nothing wrong with a pump gun or a semi-auto....and personally, I'd look seriously at the Browning BPS Hunter model in a 12ga, with changeable screw in chokes, in a 28" barrel for a good pump gun - new they're around $ 550 - $ 600....
http://www.browning.com/products/cat...id=012&tid=211
Its a lot of gun for the money ....and a gun, regardless of where you go with the clays hobby - that you'll keep for a long time.
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If you want a semi-auto ....look at the Browning Silver Hunter series...again in a 12ga, 28" barrel ...
http://www.browning.com/products/cat...id=011&tid=350
around $ 900 in a 3" chamber....and again, a good solid entry level gun in my opinon. Its gas operated...vs Inertia operated like the Benelli's ...but the Benelli's are more money....
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O/U's are the primary choices over the long run ...2 barrels, 2 chokes so you don't have to compromise on choke over one bird vs the 2nd.../ better weight, better handling, you don't have to pick up your hulls, etc....and the better guns like a Browning Citori XS Skeet model in 30" barrels is a million shell gun easily but they're also selling for around $ 3K right now..../ but it is by far one of the most versatile guns in the Browning Citori line of guns - especially with the adj parallel comb and 30" barrels...