Favorite 3.5 settings
Having DM'ed both, I can strongly recommend both Monte Cooke's Ptolus and Privateer Press's Iron Kingdoms. Monte Cooke was one of the designers for 3.0, and Ptolus is his 3.0 playtest campaign setting. Honestly, no other 3.5 product comes close in utility, quality, and completeness. It is the ultimate sand box.
Iron Kingdoms is kind of a pre-Victorian Steam Punk setting, well thought out, beautifully envisioned, and avoids many of the pitfalls of a standard 3.5 setting. Much better than Eberron. Their one pre-built adventure is not that great, but the setting, and the campaign specific mechanics, are fantastic. Plus, it's supported by their beautiful miniatures line.
Smeelbo