When we designed out new bathroom, we didn't have the contractor build in any storage in the shower area (partly because I couldn't make up my mind about what I wanted). Instead of buying another over-the-shower-head caddy, we opted for these wire bins from The Container Store, which mounted onto the tile with glue. I'm very impressed with the quality of the wire bins and they really hold the weight of the toiletries without falling off the wall. If you're looking for an easy and attractive way to store shampoos and soaps in the shower, this is a great option.
Be sure to follow the package directions when you install these bins -- we opted for a time when the shower was bone dry just before we were headed out of town for more than a day, so the glue would have time to cure. Easy Lock Pro! Stainless Steel Baskets from The Container Store, $25 and $30.
I also opted to decant our shampoo and conditioner into these simple, plastic pump bottles from Muji. It may seem silly to some, but I like not having to look at the product labels and the pumps are super-handy. PET Rectangular Pump Bottle - 280ml - Clear from Muji, $5 each.