I agree that Peercoin is a really excellent alternative - it is based on a really good idea that cannot now be implemented into Bitcoin, and does have a decent supporter base (for that very reason) compared to some other altcoins. I'm not sure how big their development team is though, I wish more people would stop faffing about solo starting unoriginal coins and put their collective time and effort into developing radical new features for a project like this. At the very least, a successful altcoin needs a large enough pool of developers to be able to keep up with Bitcoin development - constantly evaluate and implement (where useful) all the advances being made to Bitcoin, and indeed other cryptos - whilst simultaneously trying out and implementing revolutionary innovations. Even if it does get in some brilliant new features, if it doesn't keep up with the comparatively tame but constant developments of Bitcoin then its advantage is significantly weakened. In terms of new features, I'd personally like to see a messaging layer (so that nodes/clients can communicate with each other directly over the network for more complex tasks like multi-signature contracts) and greater anonymity (e.g. ZeroCoin).

Litecoin on the other hand I don't really see the point of. It's only original feature (other than scrypt which really makes little difference to its usability) seems to be that it was the original clone-coin (discounting Namecoin, which btw is an excellent alt). They have a lot of backers, but mainly just people who hope that it will boom like Bitcoin - there doesn't seem to be much particularly radical going on with it, so personally I think it's a waste of time. Bitcoin will need to get huge before any other crypto gets a look-in, and by that time others (like PPCoin) will be big enough to take on LiteCoin. BitCoin's #1 spot is guaranteed for a long time yet, but I wouldn't be so sure about LiteCoin's #2 - especially considering that by investing in LiteCoin, one is accepting the premise that alternatives, with much lower market value and market share, can be worthwhile investments for the future - so what's to stop those same investors moving to an alternative alternative, if it starts to look significantly better. The #2 crypto will be one that offers superior function.