When we were cruising around a while ago in our Phil & Ted's Sport, I was thinking about how we ended up with the mix of storage/sun/trouble-shooting solutions that we have. Most of them aren't made by Phil & Ted (sorry guys). Here is a quick rundown of how we pimped out the Phil & Ted's Sport (not out of vanity, but out of necessity):
We started with the Phil & Ted's "Hang Bag" console and quickly returned it. The three pockets - in order - are: bottle, larger unstructured zippered pocket, bottle. Both of the bottle pockets are open on the bottom which is great for bottles or sippy cups, but no help if you want to drop - say - your house keys or your phone in there (if you do, they will bean the child in seat #2). We found the center zippered pocket to be too large, too deep, too dark and generally too easy to lose things in.
Out of necessity we strapped on our Baby Jogger City Mini Console and found that it fit perfectly. It has three structured pockets - in order - are: mesh cup/bottle holder, square flip top "cooler" pocket, and another cube shaped compartment. The mesh cup holder mesh on the sides and solid on the bottom so it is great for an iced coffee or your keys or loose change (or all of the above). The two square pockets are solid, structured cube shapes and are great for Blackberry/phone, mittens, bows, toy trucks, etc. I use one of them for a pump bottle of hand sanitizer, a travel pack of tissue and a lip gloss.
There are no seat back pockets so where to put your wallet? Due to the placement of the second seat (and tipping issues) you can't attach a diaper bag to the Phil & Ted's Sport. I've seen a few creative parents figure out how to attach one to the side of the stroller frame, but it is very difficult to attach/detach. Phil & Ted's came out with the Mini Diddy (tot-sized mesenger bag that attaches to the back of either seat), but it doesn't hang flush to the back of the seats so doesn't work well for practical day to day walking around. It basically bangs you in the shins the whole time.
Instead we chose to go with a pair (sometimes a trio) of Skip*Hop Saddle Bags. One on each side and one on the bar taht runs along the top of the 2nd seat. The small size of the Skip*Hop Saddle Bag means it doesn't hold a ton , but it gives you a great place for your wallet, wipes and a few diapers (it can even hold a Potette + diaper).
So we bought the Phil & Ted's double rain cover. Its bulky (350 cubic inches tightly rolled), but it fits pretty well. Just make sure to put the second seat upright (non-reclined).
If you've met me driving my P&T in the summer you've probably heard me gripe about the TERRIBLE sunshade on the P&T Sport. Really - they're a joke. If the sun was shining down on you from directly above, it would provide shade for Tot #1's head (but not her shoulders, arms, body or legs). Since the second seat is tucked behind and underneath the first seat, Tot #2's legs are always shaded (but not necessarily his head, shoulders, arms, etc). You get my picture. The "sunshade" looks kind of like a sunshade, but it does not actually provide any shade from the sun.
I love the Protect a Bub Compact Sunshade and the Protect a Bub Tandem Sunshade (shown) which provide great sun coverage (UPF 50+) and store very compactly (included 8"x8" drawstring bag). They attach to the stroller with a set of fabric ties and can easily be pulled back/tucked up to take kids in or out of the stroller without having to fully remove the sunshade. They are also cross-compatible with a lot of other strollers so it is something you can hand down to friends, siblings, etc. after you're done with strollers.
For the babe we started out with the Phil&Ted's Cocoon, but quickly returned it. It was very, very snug fit in the 2-child infant mode and was difficult to get in/out of the reclined main seat. If you live in a cold climate and need bundlers, the toddler size JJ Cole Urban BundleMe is a good option with a little compromising. For the main seat, skip the elastic band and pull the top pocket over the top of the seat (you may need to undo the two clips at the top of the seat under the canopy). The child shoulder straps should hold the rest in place. For the second seat, pull the elastic band all the way around the seat frame and pull the top pocket over the top of the fabric portion of the seat (below the bar). If you are using this in infant mode (second seat mounted on top, main seat fully reclined), you can use the second bundler in the full reclined main seat. Just make sure to tuck the top portion of the bundler away from the baby's face.
If you have a toddler you probably will need a potty seat. And it just so happens that my favorite potty The Pottette Plus seat fits pretty well in the Skip*Hop Saddle Bag which can be strapped on the side of the stroller frame.
For a light grocery shopping trip, bulky/heavy items are best stuffed in the basket under the stroller (if you have room), but you can hang a couple bags of lighter items off a pair of MommyHooks on either side of the handlebar. The MommyHook is one of my favorite inventions. Between all of our strollers, I think I own about six of these. Two have already been worn to death and had to be replaced. Make sure to balance your load equally between hooks, checking that the bag don't swing near child #2's head, and make sure you install the clip opening facing out for easy access.