This thread was all very interesting so I thought I'd mention that I bought the Turtle Wax Ice Synthetic Paste Polish about six months ago.
It sounds similar to the Autoglym product being described, and is also quite expensive (though not *as* expensive) - you get a blue foam applicator and a blue microfibre towel.
Generally I don't go for this sort of stuff - I use 'trade'-type polishes such as 3M Finesse-It which comes in a large and economical bottle. Most of these are just cutting compounds which leave the paint smooth and the customer happy.
Actually I did try the Mother's '3 step' system - the paint cleaner, the glaze, and the aforementioned wax - I found that after the glaze was buffed off, the surface was so shiny that I couldn't get any wax to stay on there! Never mind the fact that it took ALL DAY to apply the three-step system...
Anyway, getting back to the point, I decided to try the Turtle Wax Ice. The first thing I noticed was that it is not abrasive at all. This is fine for those of you with new cars (or cars that are only a couple of years old) but for those of us with older paint, you need to get rid of water scale, tiny red spots, dull areas, etc. first. You can feel most of this if you run your hand over the paint after washing the car - it's surprising just how rough the paint can be.
So, I went over my Punto completely with a clay bar and then the Mothers Paint Cleaner (this is basically a fine cutting compound in a liquid form, probably similar to T-Cut). The clay bar gets rid of the worst contamination; the paint cleaner gets rid of scratches, previous wax residues, oxidised paint, etc. As I had just bought the car, I wanted to give it a treat.
Then, once I had a nice smooth and shiny surface, I applied the Ice paste.
This part was really easy and the results have proved impressive. The car has only been washed a few times in the last six months, yet it always looks shiny and clean. The water still beads nicely - even though it is more than six months now - so I'm very impressed with it. I will only have to reapply the Ice paste, rather than re-polish the car. I have used various waxes before (Polyglaze, Re-Po, Meguiars, Mothers, Autoglym Super Resin Polish, and some no-name types) and I can honestly say that the Ice paste has lasted better.
The other nice thing about the Ice paste is that it is actually recommended for black plastic trim etc. so that's much easier than having to use a separate product, wiping it off, etc.
I am one of those sickos with a big collection of different products (as thepottleflump mentioned), but for someone new to this sort of thing, I'd recommend a Mothers Clay Bar kit, a paint cleaner (silicone-free fine polish) of some sort, and the Turtle Wax Ice. It's all you'd need...
Cheers,
-Alex