Although I'm not fond of more than 7 Keystrokes to a .mobi name, you picked up enough good ones to "hedge" your bets. Also with the amount of attention yet to be stirred up with more auctions that will last until 2008, you could easily flip these at any time during the next couple of years.
Personally, I wouldn't sell your names. Development in this space will be very lucrative in a very short span (maybe two years). More marketers will be slowly migrating towards PC ads, but as soon as Christmas 2008 hits when all handhelds have the latest internet offerings, you will then see a HUGE amount of money flow into this market. An obscene amount. Again, there are more handhelds (4x's more) than PCs. Everybody carries their handheld's with them. We want them to do more, but no one has "pitched" us a good internet offering with our phone plans (will soon change).
As far as buying anymore, I would stick to only the best. I like Save.mobi the best out of all your names. This name sounds like a coupon "destination". Marketers will be falling all over themselves to offer coupons via handheld devices in the next couple of years. I was reading a article in REVENUE mag that predicts "paper" coupons will all but be extinct by 2008.
Good luck, and remember. Buy short!