Be very careful about buying Globals (or any other decent set of knives) online - there are an awful number of fakes out there. Global has a bit on their website about it, along with things to watch out for, but stick to the approved retailers if you can.
How long they're sharp for depends on your usage of them - get a steel, but buy some whetstones for sharpening them with. Use them properly - don't attempt to sharpen the knives with the steel by grinding away with it - that's not what it's for. Make sure you have a nice (flat) chopping surface and don't do something daft like use them on a glass board or something.
Aside from that, they're great, but you'll also love using any of the brands listed above. Get down to a decent shop and try them out for size, weight and balance.
Great advice, thanks I'll head into town at the weekend and see if I can find somewhere to try them out.