Which new iMac?

HI all,

I'm a PC user but am seriously in need of an upgrade. I am thinking of getting one of the new iMac's but am open to anything really.

My question is egarding the graphics cards on the standard iMac models. Money is a concern but I also don't want to buy something that is not going to keep up with my usage in a year or two so I don't mind paying a little extra. My needs are fairly basic: internet mostly, viewing sorting and posting photos from phone and camera and the occasional game when the misses isn't looking.
I am wondering if the NVIDIA GeForce 9400M will be adequate for my needs or if it will be a little slugish with photos etc. or would it be wise to go for the ATI Radeon HD 4670?

I have also seen a Toshiba laptop that is half the price of the basic iMac, the Satellite L550d (on offer) that could be an option. Specs: 17.3" Backlit LED, AMD Athlon 64 X2 Dual-core mobile (2.1GHz), 4Gb RAM, 400Gb HD (5400 RPM), Ati Mobility Radeon HD 4570 (512 Mb). Would these specs be adequate for me to work with photos and some games without being a total drag in performance terms?

I am unable to try any of the systems first hand as I live in Norway and the shops are rubbish so would have to order online.

Some more informed opinions would be appreciated. Cheers.