To really confuse the issue -- drop into the Touring forum and learn about road bikes that are made to keep you in the saddle all day. I made the move from a hybrid to a touring bike after six months of commuting. It's been fantastic. Also, if you want to get a great deal, everyone's heading to REI in March to get 20% off. (No, I don't work for them -- they just have great bikes at great prices this month, so you can get a lot more for your $700 budget.)