Sky is pretty turgid I believe, but you get what you pay for I suppose.
Try, if you can be arsed, unplugging everything but your broadband modem/router/hub (just to test of course), also if that doesn't improve it, take the faceplate off the phone point and plug into the engineer's socket, if it still sucks, you're just getting shafted (or you live in a really old part of town and the broadband is getting to you down some barely connected copper oxide). Ours was fucking us about and we got MUCH better speeds by putting the modem in the hall, beside the phone point, connected straight to it by just the little lead you get with them (no 40ft telecoms infrastructure projects as we previously had). The reason that is good is that the phone signal is infinitely more fragile and susceptable to getting fucked on a long cable run, than will and ethernet signal (ethernet will lose it's sync over distance before the signal strength degrades, apparently).
Obviously if your machines are connected to the moden via wireless, you're basically just cunted, wireless is snakeoil bollox unless you're only making light, non-critical net use, and you're 5 feet from the access point.
I use my O2 dongle with my Asus 900a netbook (great machine, but the linux installed when it arrived had to be replaced with Ubuntu-netbook-remix, because it acted like Vista, fucking with the hard disc for no reason.....bloody odd because the Asus 900 I bought for my mum, identical except OS version, CPU and hard disc, runs like an absolute DREAM). I've had it running at 2meg/s before, but usually 1/2-1meg. Their DNS servers are bollox, and drop offline a lot (this is when the browser says "looking up neworderonline......." forever), so I fed it the IP addresses of some public access DNS servers, cos I'm cleverer than it!
I do so little in windows, that I rarely have need of cleanup progs, though I do have a wee spring clean now and then, usually at the same time I run adaware,spybot and AVG (usually they are disabled, I rely on having a clue, and being lucky).
In linux cleanups are not usually needed, you have a "home" folder, where every single thing you do is saved....all your personal program settings, your desktop, internet cache, downloads, the lot.....sort of what "my documents" SHOULD work like. When /home/steve gets a bit full there is an amazing proggy called "kdirstat" (for windows, "windirstat"...ported straight from linux), which shows you all your folders....sorted by how much stuff's in them.......makes finding the self-emancipated-african-american-in-the-winter-fuel-stocks a doddle....give it a go.
PurpleWorld are scamming fucktards but now and then you can weasel a bargin outta them.