The desk top vs laptop is always an agonising choice for me. I do a lot of work at home...but also quite a bit out at local theatres.
My four year old Lenovo with an I7 does the job well. I run Audition and Premiere Pro and can handle mixes with a track count in the 30s no problem or edit HD video--for this sort of thingI can add a second, larger monitor when at home but still have all I need when I'm out and about. It also runs a programme called Show Cue System which I use for live sound playback in theatres.
Having said that, I get nervous every time I put the computer in it's bag and go out so I'm seriously wondering if, next upgrade, I should divide the money and put a very powerful desktop in the home studio and have a cheaper laptop for location stuff.
Decisions, decisions.