Basically, my scenario as well.
I just rebuilt my MythTV box a few weeks ago after it developed a mainboard issue. So, I decided to upgrade it with an SSD for the boot disk, new OS install, and newer mainboard, proc, and memory.
Honestly, it doesn't take that long to set up. It took about a day to get running the way I wanted, including the hardware work and futzing with the EFI BIOS on the new board.
Here are the installation steps I took:
0. Get the hardware work done.
1. Install Scientific Linux 6.2. 2. Install EPEL and ATrpms repositories and yum-priorities. Set up yum priorities to put Base before ATrpms, and ATrpms before EPEL. Make sure the storage is all there (NFS and local RAID1). Install Base package set only.
2. yum -y install xfce4 mythtv
3. Manual work: download the "firmware" for my Hauppauge tuners and stick in /lib/firmware (5 mins). Download, compile, and install latest lcdproc package (10 mins). Copy the MCE remote definition to lirc config. Make sure that udev doesn't steal my remote and make it a linux-input device (Linux has built-in support for MCE-type USB remote receivers, but it's not easily customized as far as I can tell).
4. mythtv-setup - anyone should be able to work through this.
5. Make sure lircd, lcdd, lcdproc, and mythbackend start up on boot.
6. Log into box and run mythfrontend.
7. Set prefs the way I want them, maybe 30 minutes to go through.
8. Watch TV.
9. Since this is a dedicated box, set up gdm for auto-login and mythwelcome to auto-start, and make sure APCI wakeup is working.