My own system is the same one that Malc has, the Aquatech one.
Very much cheaper than the Omnipole setup, has the advantage of being very lightweight, lift out trolley and pop in either one or two 25 litre containers depending on size of job.
The poles used are the Unger ones, the cheapest ones out there, but very adaptable.
The hose feed is outside the pole and this makes it very easy to just use one section of the pole or all of the sections.
I also have an Unger 5ft extention pole, and a roughly two & a half foot pole. All very cheap.
All you have to do is swap the brush head beween poles, its very efficient.
Downside is when well extended it is a very whippy pole.
Being aluminium the ends of the pole where you fit the brush wear, and everything gets very wobbly. You end out cutting a half inch off and re-drilling holes for the brush to clip into.
The....for goodness sake! what is the word!! ....tensioners for tightening the poles when extended tend to wear out and break, but they are very cheap to replace.
I like the powerpole from Omnipole, I think that is the one that uses aircraft grade aluminium? Don't know if that one wears anything like the Unger one, though I think the brush is attached in a very different way.
As I understand it, it is far more rigid than the Unger poles, but also heavier too
Many attachments for it so its very adaptable.
But of course it is pricey too.
If you are the practical sort, check out the DIY guide that Matt has done, first rate guide.
http://www.cleanitup.co.uk/smf/index.php?topic=7412.0Many who go for a trolley end out mutating it into a mini van mount that they operate out of the back of their car or van, that goes for me too.
But it is a good starting point nonetheless.
I'm shortly taking the plunge and getting a van, slapping a 650 litre tank in there, I'll keep my trolley and I might even add a back pack.
If the depth of my pocket was endless I would have gone for a big van and a 1000 litre top of the range hot water system that Ionics do.
But it isn't, and we all have to start somewhere.
I think I would recommend going for one of the cheaper trolley setups if money is tight (depends on vehicle too of course) and upgrading from there as you go along.
They all do the same thing untimately.
Ian