I *think* as far as viruses (virie?) are concerned the Apple might be the better choice. I believe Cap'n is the only Apple user on here....but I cold be sadly mistaken. From what I hear, hackers don't target the apple market as much because there are fewer of them. Apple also runs proprietary software, so I believe none of your current software (MS Office for example) would work. There again Cap'n could speak to that.

I bought a new DELL last year with Windows 8 loaded. It is VERY different from Windows XP. My old XP computer was over 10 years old, so the new one is WAY faster. The old XP box now lives down in my ham shack for use with my radio stuff.

I do not know what Ubuntu is. Is that an Internet browser? For Windows based machines, I think good old Firefox is the best browser. If you go with Apple, I *think* your only choice is going to be Safari.......but there again, I could be mistaken.