word; sounds like you want a nice road bike... go to the local shops and start test riding!

you will quickly find out exactly how light you can go for you given pricepoint. i think antything with shimano 105 or above on it will treat you well for the longhaul.

i also highly recommend geting a shop to take some time to try to get you properly fitted for the bike (this can sometimes cast 50 bucks or so). that will make a world of difference in comfort and speed.