All the suggestions so far are good ones.
The one I'll add to the mix is the Ithaca/skb doubles that were made by skb and imported by Ithaca. Thay are reliable and for the most part priced right. The model 100 is single trigger pistol grip and you should be able to find a nice one for no more than $800.00 The 280 is English grip and a little harder to find and you will more than likely have to pay a little more for it than the 100.
The one thing to watch for on these is the wood cracking at the scallops where the head meets the action. These were prone to cracking there but if you once a year or so will tighten the thru bolt and keep it tightend up, it will give years of good service.
Be carefull SxS's are addictive and all you will do is want more!