What phone shall I get?

[Casio]

I might go for the HTC Hero, does anyone know if this comes on O2

[Casanova]

the G1 and the Hero are between one to two years old. There's no point in going for either because of the outdated spec.
If you want a reasonably priced smartphone, new go for the HTC Wildfire. Nothing amazing but has everything you might expect from a HTC device. Android 2.1, 5MP camera with LED flash, seven homepages for customization with widgets and over 50,000 free apps, amazing social networking opportunities from HTC.

Shop around. Avoid ebay!