PC to Mac advise needed

OK, this question has not doubt been ask 1000`s of times so I sorry to ask such a noob question,

I have been a PC user for around 20 years or so and I am geting tried of upgrading and spending lots of money well no more......

What I want to do is convert videos so i can stream them to the xbox 360 ( a app called connect360 should do this for me I hope) and i want to mess around with pictures and surf the internet and do my website. I a very good friend who has advise me on a mac but which one there are so many versions

I was looking at the 24" i mac 2.8 intel core 2 duo but I would never use the power and i be ok with the 20" imac 2.0 or 2.4 intel dore 2 duo

I am not looking to play games as i have an xbox 360 all i want is a computer that never breaks or gets a virus or have to down load drivers for this app etc or pice of hardwere.

can anyone answer these for me

1 is the Mac O/S 64bit how much memory will i need or what do you adivse
2 I belive you can still use windows vista ? if so can yo pick up virus this way will you be able to play pc games if i want to ?

3 The wife uses Microsoft Office is Mac office compatable

4 Can the Mac be upgrading in anyway if needed

5 Thie wife gets a good discount so I will get a imac 24" 2.8 i get for around £1250 in stead of over £1400 but is it to power full for what i to do

Thanks for reading I look forward to using the mac in the next few weeks

1. Amount of RAM is your choice. You may find that the RAM that comes as standard will be enough. Otherwise read part 4.
2. Windows XP / Vista can be installed using Boot Camp, which ships with Leopard or you can buy an app to run it inside OS X
3. There are three options: Microsoft Office, Apple iWork and NeoOffice / OpenOffice. NeoOffice and OpenOffice are free and open source both of which work very well. NeoOffice does look better than OpenOffice.
4. There is a RAM access door on the back of the iMac. Buy your RAM from Crucial and fit it yourself. It is so much cheaper.
5. I like the big 24 inch screen but for the price a 2.4 processor should be fine

1. yes it is 64 bit, has been fully 64 bit since 10.4 Tiger

http://www.apple.com/macosx/technology/64bit.html