RE: Having more than one stroller...
I think the short answer is that different strollers are good for different things and sometimes people prefer a particular stroller for one thing vs. another. It is also difficult to know what you will want/need in a stroller BEFORE you actually have a baby, especially for first time parents. To me, the 2 big baby items that are most influenced by personal tastes and preferences are strollers and diaper bags.
My story is that I did a TON of research prior to buying a stroller and ended up with the PP Venezia. I was convinced that this was the perfect stroller for me. Not too heavy, took a carseat, but was also great as a stand alone stroller, etc. I really believed that I would not need more than one stroller. The reality is that after using the stroller for 6 months, it is generally a much heavier stroller than what I prefer to use every day. So I ended up also getting a Maclaren Mistral in a store closeout sale. Now I am starting to look at jogging strollers with envy... :-)
HTH,
Beth, mom to older DD (8/01) and younger DD (10/06) and always missing Leah (4/22 - 5/1/05)