Replying to SB700 vs. SB910

I'm planning on purchasing a couple speedlights to use for some small portrait stuff/indoor events and for some sports "strobe" stuff on the side. I realize both flashes are a tough thing to compare because they're completely different models and they both have their pros and cons. I'm mostly just looking for someone who has used either one of them and can say whether the extra 2/3 power that the 910 uses will be worth it for sports stuff, or if it's not an extreme difference.
Also I know that the SB700 can't be connected to an external battery pack like the SB910 can, does anyone who uses an SB900/SB910 find that they use a battery pack a lot of the time or not?
I used to have a Vivitar 285 and sunpak flash that had just been abused for the past 2 years or so and they both just died on me. I would just use them with some ebay triggers for some "strobe" stuff. I never found for the time that I was out shooting that even their battery life was not long enough and I never felt as though I would have liked to have the option of a battery pack or something so I really don't think I'll be needing it.
I know some of you guys will say "just buy more Vivitar 285's" but I really would like to use a flash on camera for portrait/event stuff so that's why I'm planning on purchasing possibly 2 Nikon flashes and not a few more cheapo vivitar flashes.
I mean, either way I'm going to have to save up for these flashes so if I can get away perfectly fine using 2 SB700's then I would much rather do that, than save up and purchase 2 SB910's.

I'm really leaning towards the SB700's but I would just like someone who has owned either one to just give me their thoughts for the best option that will last me into the future and fit my needs.

Also how well does the CLS system work? I'm probably going to end up purchasing some pocket wizards in the future but for the time being, is it alright to do a little off camera stuff? Obviously having to use some type of on camera commander sucks but it might do the job alright for a little. Just curious again.
Thanks