Hi I`m getting my first MAC ever , I was a PC user for over 15 years. I want to get a refurbished iMac but i`m stuck with a decision... is it worth it to buy the : Processor 2.8GHz Intel Core 2 Duo L2 Cache 6MB Shared Frontside bus 1066MHz Memory 2GB (two 1GB SO-DIMM) of 800MHz DDR2 SDRAM; supports up to 4GB Hard drive 320GB Serial ATA; 7200 rpm for $150 extra or get the : Processor 2.4GHz Intel Core 2 Duo L2 Cache 4MB Shared System bus 800MHz Memory 1GB (one SO-DIMM) 667MHz DDR2 SDRAM (PC2-5300), supports up to 4GB Hard drive 320GB Serial ATA; 7200 rpm ??? I wanted to get a 3rd party RAM MEMORY anyway increase it to 4MB, but is there any difference in the increase of L2 Cache from 4 to 6? and System bus 800mhz? I will be mostly doing video editing and music composition. What do you guys think. Thanks a lot ! btw. computers bought online are only exchanged by mail as well?