Sager I have heard fairly good things about, especially on these forums(Obviously
Dell, well the good thing about Dell is not their quality, but the fact you can get next day on site service for their equipment. Very useful on occasion.
Personally I would say Audio and gaming are probably going to lead you towards opposites of what you want from your machine. If you do any recording a quiert machine is going to be more important, and with gaming needing the fastest, it also tends to need the loudest cooling. 9860 is a good example for this.
As such I wont try ot tell you what to get that will do both perfectly, I will give you my opinion for an audio machine. Keep it quiet, keep it cool. Use it not for your primary machine, but rather for a mobile workstation you might be able to do some of your editing and mixing on, and get a cheap desktop that is both quieter and more powerful for your primary station, youll probably save some money like this anyways. Get an external sound card for your laptop at least(And probably for your desktop) Firewire cards work great for this.
A gig of ram will serve you well, 2 is definitly better but the main thing is to get at least a gig. As well as your choice to go with a 7200 RPM drive being another good move. Though in all honesty it is better to have your OS and your Audio on seperate drives. That way it isnt trying to read your OS when it needs to be writing Audio you are recording.