Switching to mac - specidic questions

Hello all i have several specific questions about my upcoming switch from PC to mac.

• 
  My budget is £1000 - apprx. $1700 on day of post - i can give or take $300 if there is value involved
  I will mainly be using the Mac for recording music, digital photography and video editing.

Questions:

• A mac book would be handy because I could do my music work in the music studio and photography workl in the house (freeing up the music studio for others) - can a macbook at said budget handle this? Or as a general rule of thumb would a desktop with similar budget be more powerful.
  
  I have been told I would need an I5 processor rather than dual core if doing music recording - it seems i'm more likely to get a macbook at sadi budget than a desktop. What are the advantages/disadvantages of macbook over imacfor someone with my needs?

Your budget would get you a MacBook Pro from the refurb store

Don't be put off by the word refurb, its still a new Mac with full warranty

Refurbished Mac - Buy Refurbished Mac Products - Apple Store (UK)

Thanks for the reply.

Yes, I am definitely going for a refurbished mac and have no other option. Its between a 13" with 3mb cache and a 15" with 6 mb cache.

Refurbished MacBook Pro 2.4GHz Dual-core Intel i5 - Apple Store (UK) this is £849

Refurbished MacBook Pro 2.0GHz quad-core Intel i7 - Apple Store (UK) this is £1189

I'm not noo bothered about the screen size but can't hep thinking I might be glad I invested in the one with the better processor. Is the difference worth the money??