I'm in Surbiton (Kingston Upon Thames AKA Greater London). EU to US has no visible lag and i've never experienced any problems. I've never tried Korea but I've pinged the Korean Bnet server before and my latency was very high (when it goes through China it becomes stupidly high)
To get extra accounts you need more Bnet accounts because the maximum amount of SC2 Licenses on a Bnet account is 1. I have 2 gmail addresses so that's how I got two accounts.
I've set up my NA account now, thanks

I have it linked to the same battlenet account as my EU one though. All I did was go on battlenet and go to the page where you buy games. Then I set my region to North America. Bought the game. Then I installed it to a different directory to my Eu installation. When it was installing it came up with a warning saying my replays etc in my documents folder would be overwritten, which I said "ok" to, however all those files are still intact and my replays are available for both of my accounts. I have 2 icons on my desktop, one for EU and one for NA. I log in with the same e-mail and password to both of them, but have a different character on each. My replays for EU only appear when I'm logged into my EU account, and likewise for NA. So in other words, it works perfectly
On another note, I've found the players on the NA server to be a joke. I'm currently rank 2 diamond after 15 games, and have a 50% win rate against masters people so I may even be promoted soon. On my EU account I am platinum, albeit I am way overdue for a promotion (~70% win rate against diamonds so far). I'm nowhere near high diamond though and I've never ever been matched against a masters player let alone beaten one.
It's pretty funny because my mechanics and multitasking are pretty terrible and my macro is very inconsistent (I'll stay at ~100 minerals for ages macroing like a beast, then forget to produce anything for like a minute and build up 1500 and have to throw down 4 barracks). I don't cheese or all-in either (except sometimes 111 SCV all-in vs protoss because they are a gay race). I guess people are right when they say KR > EU > NA in terms of difficulty.
...because the maximum amount of SC2 Licenses on a Bnet account is 1.
The licenses are linked to the region. So you can only have a maximum of 1 EU license, or a maximum of 1 NA one, but there's nothing stopping you having 1 of each because they are counted separately. I may even add a taiwanese license sometime if I feel like putting up with the lag to try and pwn some koreans (more likely get pwned by them)