Currently I use a early '70s Peugeot for commuting to work, about 7 miles one way. The bike was originally purchased by my father who also used it to get to work on occasion. Due to the front derailuer breaking, I am down to 5 speeds from the original 10. Also am on the original wheels, chromed steel. Other than a new seat, bar tape, brake hoods, brake pads, and requisite tires and tubes the bike is original parts.

In general terms, (realizing pictures would be probably be helpful) what would produce the most noticeable difference in terms of updated parts? I would describe myself as a casual rider meaning I don't need bleeding edge technology. Usually average about 14 MPH on my commute. Majority of my riding is unaffected by only having 5 speeds, not hilly enough. I have been on the fence about continuing with the current ride or purchasing a new bike and just wanted to get some more information about updating parts and what a difference it might make.

Also, if pictures would aid in comments, let me know and I will post some pictures tomorrow when I get home from work. Let me know if I left out any other info that would be helpful. Thanks.