You've obviously got the washing and drying thing sorted then - hard to keep black completely swirl free
Any of the ones I mentioned above will be suitable for you, they all last pretty well but if you can layer them up they get even more impressive. They are all really easy to work with too, no effort at all to put them on or take them off.
As Gav says though it tends to be a very personal thing, I've had some silly money Zymol stuff on my car next to waxes costing under £100 a go and couldn't tell any difference visually or after a period of a month or two, quite a bit of it tends to be hype, £30 can get you some really nice stuff
If you do want to spend that little bit more Swissvax Best of Show seems to be very highly regarded, I need to use some others up before I try that out though. In the meantime you might get an idea of it from this:
http://www.detailingworld.co.uk/forum/showthread.php?t=60353
I had the Dodo Double Wax they mention in this one on my bonnet for a while, next to the Zymol, it was almost identical on all counts:
http://www.detailingworld.co.uk/forum/showthread.php?t=60321
But they have a new one called "Supernatural" that's a single wax and supposed to give similar results.
http://www.cleanyourcar.co.uk/wax/dodo-juice/cat_59.html