Oh, the perfect stroller.....Don't think it exists. ;-)
I have been in search of it and found that you need more than one to meet all your needs...outdoor, travel, shopping, etc.
I have a combi twin and a joovy sit and stand. I like them both. I usually like the sit n stand for the indoor stuff, like the mall, because it is easier to get thru isles and my son can get in and out (there are straps in the back if you don't want your older one to run out at whim.
The combi is great for travel b/c it is super light and when folded you can carry over your shoulder with a strap. The seats recline for napping and you can fit your infant seat in it. The manufacturer states only the combi seat fits, but my graco fit, maybe not to the standards of what the manufacturer can say, but that seat was not going anywhere.
The draw back is that the combi has little to poor accessible storage and no trays or cup holders.
The closest thing I found to the perfect stroller to fit my needs was the Double City Mini. Last year, it did not have the option of holding the infant seat. Now it does. I am so bummed b/c I thought that one was great for everything, even jogging. I ran to someone in the mall that had one and they loved it. You can test one out at Buy Buy Baby in Downers Grove.
BTW, don't let the not fitting b/w the isles at a department store be a deal breaker for the side by side. It rarely has been a problem, b/c how often do you really shop like that with the kids. Those strollers fit thru all standard door ways.
Hope this helps.
Good luck and I hope this helps.