Here are the basic choices:
No PC: get an analog board (or ADAT input digital mixer) and outboard gear for mixdown. A popular box for CD burning & other related chores is the Masterlink.
PC:
Transfer via ADAT. That's what I do now. You need an interface with enough ADAT inputs--ideally 3

but if you don't run 24 tracks too often, 2 is survivable. I stay entirely in the box for mixing and CD burning, but once you have the files on the PC, you can do just about anything you want. I suppose in theory you don't even need to transfer, just set up level and pan and plugs on inputs and do the mixdown straight from the HD24 to PC. I've never tried that though, I like drawing volume envelopes and editing too much
Transfer via FTP over Ethernet--supposedly slow, I haven't tried it but I just got a router so I might in the future. It's faster than the real-time transfer of ADAT, but you can't work on the mix while you transfer files, so I'm not sure which is best.
Transfer via Firewire--fast, but you also need the FirePort to do this.