I feel I must give you a quick recommendation about the TomTom, I have the Version two of the TomTom One. I had the Version One, but this went wrong, and although it was repaired free of charge, I needed a satnav so had to buy this one. The cost at the time was Â£100, with a free Â£10 accessory voucher, and also a carry case.
I will start with the TomTom itself, it has full UK & Ireland, a decent windscreen mount, charging lead, and a very good instruction book. You will see these for less than the magic Â£100 barrier now though. I must say the voucher is not really worth the paper it's printed on, because there are no accessories costing less than Â£10, apart from a voice. The carry case on the other hand, is very good, and keeps the machine safe from damage. I stow all my TomTom gear into a small zip up case, including a few other bits & bobs.
The screen is very easy to read, the voice can be heard over engine noise, even trucks. The charger lead is long enough to reach any socket. I also think the windscreen mount is good enough to stick to any car or truck windscreen. It is recommended that this mount is removed & repositioned every day, but I have left it stuck there all week. This is of course bad practice, as these sat-navs are very small, and very easy to steal. Many vehicles have been broken into, just for the sat-nav, they are easier to remove than a stereo, don't normally come coded, and are sold in Pubs for Beer money.
I do not intent explaining how these work, but will recommend them. If you buy one, you will be rewarded so many times over, and will actually enjoy the idea of being told where to go.
I have had very few problems with these, and would not be without mine.