In your last post you mention that you're noticing it while downloading as well so this might not help resolve anything but I believe it's worth a shot. Have you run a trace route? I didn't see anyone else mention it here so here are links to both versions:

US Trace Route
EU Trace Route

A trace route will determine whether it's really you or whether it's the outside world messing with you. If you'd like you can run one from your laptop as well and compare the results. I have been using that registry 'hack' for quite some time and it's only lowered my latency. Everyone I've shared it with...it has only lowered their latency. I can't think of a reason why you'd have high latency on one machine and not another. If this is still an issue you're probably better off asking on other 'real computer' forums like http://www.sevenforums.com/.

Hope you can remedy this problem soon I'd be ready to break things at this point