I don't see the manga ending any time soon. Aside several plotlines that haven't been tied, there are several character arcs that I could see coming to the forefront; things such as Gokudera's relationship with Bianchi and the rest of his family as well as Yamamoto and his father's relationship to Tsuna's father, etc. I would really like to learn about those!
I'd absolutely LOVE to see a time skip! It would seem that the best time for one would be after this arc. It would be great if Tsuna did inherit the Vongola's Pride. Time skip a couple of years (to where the guys are no longer at the creeper age of 14-15) and see some of the things Tsuna does as Vongola boss! I would love it if that happened... wishful thinking, though as far as I know... Amono先生 has this amazing talent of being able to twist plotlines so much that you can never see half of what's coming. ^^