based on my experience, id go with hp. ive messed with dell, ibm, hp, micron, sony all that madness. HP has always been on top. but if your concerned about memory, i think your best bet would be to get someone to build you one because the companys tend to grab generic hardware and toss it in there. . you can get high end parts and most of the time spend less than what you pay for a company made computer. it also depends on how you are going to use it. if you are 100% software, then you would want to beef up on some good ram and a good processor. i had an old hp and it was dope. but with only 512 of ram and it would run sluggish when i would use mutliple vst plugins. i built a new one and it cant be f@#ed with no matter what you through at it. my advice is when you want a new computer, the first thing you ask is "what will i use it for". since you said music, the next question is "how much do i want to spend". bottom line, for a company go with HP. if your interested on getting one built, i can show you what to look at depending on how much you want to spend. you can build a monster for 7 or 800. hope this helps
