For the moment it probably won't really matter a whole lot but since the ClassicCoin altcoin has different consensus rules from Bitcoin it could potentially end up on the wrong side of a fork if it had its activation trigger. The way the ClassicCoin altcoin is programmed it could easily create two viable chains if it hits its activation threshold. Those who don't want to change to the altcoin should make sure they are following the Bitcoin chain and not the ClassicCoin chain by mining on pools that have Bitcoin nodes and not ClassicCoin nodes. As long as the ClassicCoin's activation doesn't trigger you will still be able to spend the coins as Bitcoins however.