I would not try to sell as a package. Do not renew the others but keeps and build the .com into a minisite or blog. Direct the other domains to the .com until they expire. If they get traffic then renew. One you build traffic to the .com think about selling that alone. For the small amount of money you will most likely get the future owner will not want to incur all 7 of those domains with approx $80 in regfees.
This is what I would do. Good luck with whatever you choose to do.
great domain name...
i would have kept it and developed it and then put it up for auction.
high $xxx if undeveloped.
You may think of having all extensions as being a good idea. (google for example) But for us small guys as long as we have the .com we are kings.. We do not need the .info or .mobi.
Also, if you have the .com and someone else owned the .net and they developed the .net into a site you could approach them to buy the .com
(One more potential buyer that you do not have now because you own all the extensions)
I'm rambling..

