Thanks guys for all your help! I've been currently using a Mr. Clean spot free rinsing system to lessen the water spotting. I still dry the car anyways, but there are always going to be certain hard to reach areas of the car that are extremely difficult or impossible to dry completely, such as the door jams where the hinges are, especially the ones near the front fenders and the engine compartment when performing engine cleaning duties.
I used to bring my own wash bucket to the self service carwash and use the spot free rinse setting there and most of the time it didn't leave any water spots. I find the self service carwashes especially useful when the car really doesn't need a full wash, but rather just a quick rinsing to get rid of dust (also brake dust), bird droppings, debris from trees or in the event that I happen to drive on a wet road. I do not dry the car after such washes. What I do is drive on the highway for a few miles and then pull over or wait until I get home and carefully blot the dirty areas behind the rear tires and on the rear bumper to remove the dirt that stuck to the car when it was driven while wet.
I want to upgrade from the Mr. Clean system since the filters do not last very long and are fairly expensive to replace on such a frequent basis. I am strongly considering purchasing the deluxe filtering system that Autogeek is selling, which is said to remove minerals and sediment in the water with a two part filtering system. The kit sells for $120.
Has anyone had any experiences with this kit or know of someone who has? It seems like a pretty good deal considering the spot free system that I read about in a previous thread was around $300 and I don't think that one is designed to filter sediment. There was also another one discussed (I think its called CR or something like that), but I didn't see to much info on that one.