Advice please. Was about to change old PC to buy a Mac as already have I Phone and I Pad. I know that some stuff wont work on the Mac but understood I could buy Windows for Mac to  transfer all my Office based stuff. I have a website created on Windows apparently not compatible with Apple Mac so now having a rethink whether to just buy a better Windows PC on same budget?

I'd go for a Mac. I switched to a Mac laptop about 5 years ago and also got a Mac desktop about 2 years ago, would never recommend a windows PC again. The majority of things you need you an get for a Mac (Ive got office and all office documents on a windows PC work with it).

I'd go for a Mac too, particularly as you already have other Apple products. The lack of virus problems is a huge plus in my book too

If you get a Mac you can get a program called "parallels" which basically opens up a windows desktop on your mac computer. You can install or run anything described as "not mac compatible" on there. I have a number of clients that use mac, and many farming program's don't run on macs system - but run fine through parallels. :)

There is no reason why you can't manage your website on a Mac.
If you have an FTP programme which transfers files to your webspace, that's no different in Mac or PC.
If you were using a PC based programme to create your website and maintain it, then that might be more awkward, but Mac programmes are available to do the same thing, and can often be easier to use.

I am at the opposite end to you having owned Macs for many years, and now having to negotiate PCs. I'd go back to Mac in a heartbeat if I could.