Let me be the first to recommend a nice Japanese gun - a Browning BSS 28" Sporter. Straight stock, slender semi beavertail, single trigger (for when it's cold and you're wearing gloves), 3" chambers and if unmolested mod/full chokes. Should come in around 6.5 pounds. A pheasant killing machine that you can stuff any load you want into. They handle well, are amazingly reliable and cost around $2,000. They are a little tough to find. American classic SxS guns are neat, and I own a few, but old guns are like English sports cars - if you want to use them you better know a good mechanic/gunsmith.
I would also recommend a Beretta 470 or 471. I had a great 12 gauge 470 with 28" fixed chokes, straight stock, splinter forend and single selective trigger. This was the most reliable SxS I have ever owned as it never broke or malfunctioned. I put thousands of rounds through it and shot piles of birds. The 20s come in any configuration you want.
http://www.gunbroker.com/item/564133083You could get a Winchester 21. An American Classic you can shoot hard. A bit more money. Here's a nice pheasant gun.
http://www.gunbroker.com/item/564175735Have fun shopping.
Jeff