Resolved Question: Windows XP or a Linux program?

okay now i have used Windows 95 all the way to Vista and well now i have ran XP the longest love it but i am a guy who gets bored with samething and i here you can customize and do so much more with Linux instead of Windows but the question is which is better for what i want i run
1:MP3's i do music i download love to Frostwire
2:have to have Office 2007 for school
3:not to big on games
4:fast i looking for speed in a Compaq Presario SR1103WM with 30GB hard drive, 512 RAM 2.53Ghz processor celeron D
5:i do transfer music from computer to memory cards and MP3's too so need good music player i use Windows Media Player and well hate Apple products period and have tried VLC but wondering if there is better program
6:i have to have Firewall and Anti-Virus protection even though most viruses and trojans etc... don't mess with Linux or Apple still want to be safe you know put mind at ease i guess lol
7:already run Firefox best out there
8:also updates
9:i want something user friendly and well everything works on Ubuntu so that not problem however partitions suck and messed computer up the CD now won't boot right and well i had to reinstall windows twice to fix it and full system restores

by any chance could i get answers without going to another website sometimes they not clear at all and different ways to run it and if i should use windows still and have Linux on side can i put it on USB and use Linux that way just different things Thank You
Okay now i need some programs that are good to add to Ubuntu