We know/knew nothing about you being able to see with or without glasses, and we can't possibly know if you have an eyesight issue or to what extent. Blackberry, iPhone/iPod, Samsung and HTC all do large (full) screens, with Samsung and HTC having some of the biggest screens on the market. Really, you need to get down to a decent phone shop and hold the devices in your hand to see what you think of them, as ultimately the choice is yours as to which you prefer.
As for a service, no, you didn't mention it in your first post. I mentioned about using an iPod Touch if you on'y wanted to download via wifi instead of cellular data plan, as using UK data plans abroad will incur expensive roaming charges. Again, you need to speak to the carriers to see if/who does outside UK data plans for what price
I have an HTC Incredible S which has a 4 inch screen. It's great for emails, I've been very happy with it. It's the first phone that I've had which has really hit all the buttons - I had an LG Viewty before that which wasn't good enough, but the current generation of smartphones is great and getting better all the time.
So really anything with a decent-sized screen will probably make you happy (the 4" screen of my phone is a reasonable minimum IMO). If you have the pocket space, a tablet will be even better for emails, but they are significantly less portable.
Thanks for the various replies, the Galaxy S2 was a bit strong for me so I opted for the cheaper Galaxy Ace.
It does what I wanted and the screen size is tolerable. The only thing I notice is the short battery life when I'm using bluetooth in the car. I did notice that my previous old phone, an ancient Nokia, had a short battery life when connected to bluetooth. I guess this is something that affects all mobile phones?