I love retro bikes, that's why I visit this site.  I've raced since the 80's and you can't beat the look of a classic quality steel bike.  I've got my classic Rory O'Brien with campag super record and down tube leavers and its a thing of beauty to have in the garage.  I even ride it occasionally on sunny days.  However, there have been advancements which make cycling better and going fast easier.  A wide range of gears you can change seamlessly from the handlebars even out the saddle are fantastic.  Clipless pedals as someone has already said are a lot better than clips and straps.  But here's where I know not everyone on here will agree, you can't beat the ride quality of a modern carbon frame.  They are light, stiff where they need to be and comfortable.  Something like a 4 year old second hand Giant TCR Advanced with 105 will cost less than a grand and is a joy to ride.