Looking to upgrade

Currently, I have 2 760s in SLI. I'm looking to upgrade, but I'm not sure what the best option would be. I have 2 monitors @ 1080p/60Hz. I would like to upgrade one or both of my monitors to 120/144Hz. I've been looking at getting 2 780 TIs, or waiting for the 880 to come out, however I would also like to make sure I'm not just completely wasting my money. I'm open to any and all suggestions, and depending on how hot the cards run, I'd like to look into third party cooling as well. Any help would be greatly appreciated.

Well, even if you perfectly double the 760's performance (which never happens with xfire or sli) it is only just getting over a single 780 ti, so the upgrade will definitely be noticeable, especially considering that your contemplating 120/144hz monitors. As for waiting for the 880.... it's up to you and your patience, as Nvidia is being hard to stake down a release date and even when they do it has been pushed back a few times. Though I would expect a reliable release date around the corner, anything could happen.