PowerBook is dying. I need to encode for transferring DVD's, run iPhoto, would like to operate the new software on learning to play guitar and some infrequent video camcorder transfer and editing. Figuring it will be an iMac or mini. I do have a 26" monitor for use if needed. What's the best cost efficient choice, but will get the job done? Also, would buy a used system if it was sufficient. Thanks