iPhoto syncing and backing up options
I am looking for advice on the best solution to sync my iphoto library. My library is very large probably 70GB. I have an external backup but I don't backup my laptop enough so I am worried I will lose a lot of photos and videos when it fails someday. I am looking for a syncing solution that will always backup my iphoto library and allow me to restore it if it crashes or my hard drive fails and I need a new mac. I am looking for the most reliable solution. Cost is a factor, but not most important. Thank you for any advice!
Any opinions on these backup/syncing options?
1. Carbonite?
2. Dropbox?
3. Google Drive?
4. iCloud? seems very expensive and does it work or is it glitchy?
5. Time capsule?
OS X Mavericks (10.9.2), Mavericks, 16GB memory, 2.4 Intel