Right now poison is the hot topic in Commander, but give it another month or two and people will be building around Battles and Lord of the Rings cards
Vintage games can end on turn one, but it is extremely rare
The tournament rules (found here) which come into effect on 1st October, 2012 are nicely summarised by Tobby Elliot on the DCI Magic Judges blog (found here)
Artifact destruction, enchantment removal, and graveyard hate are all essentials in Commander, and this puts all three on one card
Use booster packs to build and customize your deck with abilities and characters beyond those found in starter decks
Tenacious Underdog wont be able to hang in a lot of high-power Cubes just as a matter of aggressive black decks not being supported, but I expect the card to excel in the Arena Cubes and really any Cube with any sort of aggressive slant to black