+1 for Linode. I've literally never had a problem. I'm a huge fan and I'm picky as hell.
The overal quality of their (Hurricane Electric, not Linode) operation is poor, historically they have been lax on shady people colo'ing rack space in Fremont (google hurricane electric mccolo), HE-1 is full and so little room for expansion and its on a fault line.
I've NEVER had any of these problems in Newark (which is Linode's geographically local DC as they are in NJ) or London.
However I chose Fremont because it's the closest datacentre they have to Australia. Most of my readers are here.
(see http://www.linode.com/speedtest/ for pingable hostnames of servers in each DC + speedtests)
If you do want to move, you can put in a ticket and they can move you between DC's with no downtime I believe or just replicate your instance and switch IP's.
However, I've learnt, and hopefully have others, that having everything in one basket isn't the best option, even with how excellent Linode are, they are at the mercy of HE etc.
So now we have a split between Fremont, Dallas & Newark.
It's worked pretty well, we are most happy.
Anyone running a large app or site would do well to run multiple systems with Linode across multiple sites where possible.