You should definitely upgrade, many of those parts (that you already have) would be very useful/valuable in a modern build. Just add those new parts and you're good to go for awhile.
If there isn't a Direct CU II 780 ti, there should be one coming. Here is the link to the MSI Twin Frozr one though, which is also very good:
http://goo.gl/0II3AW
The Air Series fans aren't too good in my opinion. If you don't care about looks I'd go with the Noctua NH-F12.
Unless you only want them for the LEDs then in that case go for it