I never thought I'd have a stroller collection! With two kids we have 6 strollers. Let me explain:
1) Graco travel system (We used this giant bulky thing every day until D1 was about 14 months old and we smartened up and got...)
2) I'coo umbrella stroller (love this, not flimsy but small and compact and we use this if out with D1, who is 2.5 years old now)
3) Graco Snugride stroller frame (Got this for D2 because no way in heck was I going back to the travel system stroller. This stroller frame is amazingly light...love it)
4) Britax B-Agile double (Got this now that we have two kids...Hope to bust it out this spring)
5) Cheapie flimy umbrella stroller bought for $25 to take on vacation...I didn't want to risk breaking/losing the I'coo. This cheapie did its job and lasted us
6) 2012 City Mini single stroller: I bought this on super sale because soon D2 will be too heavy for me to still use the stroller frame. I take her out alone sans D1 and needed a lighter stroller to use that had good support.

So there you have it. We are one of THOSE families with a billion strollers. Ugh.