I live in Canada, and will be doing 90% of my calls within Canada. I will occasionally be traveling to the UK, Paris, and Frankfurt and would like to be able to use my phone there as well (mostly within the UK). I was looking at tri-mode phones, but I'm a bit confused if a tri mode phone will work in these places. The one I am considering is the Sony Ericsson K510 .It comes in two models, one with GSM 900/1800/1900 and the other GSM 850/1800/1900. Now if I was to go with say Rogers in Canada, its network is 850/1900, and if I had the phone with 900/1800/1900, does that mean that I'll be limited as to what coverage I'll get since I don't have the 850 band, or is that not used much? If I get the American version (850/1800/1900), will it work in Europe without the 900 band?