Wow - didn't realize this thread was still going! I've recently used purple extreme, green oil, prolink, halfrauds bike spray, makt, a couple of others I can't remember the names of... and, erm... they're all very nice! That's my fully researched scientific conclusion. None of them break the bank so quibbling cost would be quibbling pennies, and they're all oily. I lube the chain every ride now cos I can't be bothered working out whether it needs it or not.
The fact that I get through less chains than I used to is probably more to do with the fact that I'm less of a wrecker, i.e. less fit now that I'm a crumbly, rather than the fact that most lube I use now has fancy technology.
Thanks for all the replies!