I like alt coins and have owned a fair few over the last year.
Most of my current value is in Litecoin, but only because it actually has a real cash value away from bitcoin. I also like Peercoin and recently got very interested in Nxtcoin.

However, the trick is to realise that alt coins are the future.  Bitcoin is currently doing the work of introducing crypto currency to the masses, but it isn't going to be the coin used by the mainstream.  That is going to be an alt coin.

History teaches us that change comes through little differences. Technology is no different, and the past 20 years has seen so many examples of this.  The internet started for the public with glorified text files.  By today we can video chat with individuals while we watch live TV and shopping with international traders all on the same screen!

What bitcoin fanboys need to remember is that none of the above example can not be done with the glorified text file internet of 1992. 

Bitcoin gives us structure
Nxtcoin gives us proof of stake and true decentralised trading
Just remember it took years of awful search engines before Google turned up and gave us everything we wanted. Nobody remembers the first search engines like webcrawler and Altavista - yet without them, Google would not exist.
The next alt coin will give us the next step towards everyday use, and the cycle continues. 

If you are not diversified into alts, your bitcoin pension pot is going to be worthless! ;-)