How do I chose what tripod for a DSLR I should buy?

I need a good, non-professional tripod. I may carry it around at times, attached to my camera bag, so I'd definitely prefer it light and compact when closed.

I am looking at Manfrotto lineup, as it is quite popular here and you can really find them anywhere. But I am a bit confused and I don't fully understand the difference between the various series.

What would you guys recommend? What should I be looking at?