MediaPortal is a hacked together mess and it's an absolute bitch trying to figure out how to do things with it. The documentation is minimal and what's there is way out of date. Tons of plugins for it are for old versions and no longer work any more and to figure it all out you have to just go searching around the forums which are a total mess. (BTW this idea that just having forums to document your software is okay is totally false; forums are an okay way for people to interact during development, but they do not provide a useable way for new people to learn about something because you can't figure out what information is still true or not).
MediaPortal starts up really slow by default, but you can go into the settings, turn on expert mode, and disable lots of stuff like animations and all the plugins you don't want.
Setting up MediaPortal for a remote is a huge bitch. The best way with my system seems to be to set MediaPortal for generic HID input, which makes it take key presses, and then set the iMon thing up to output the right key presses. There are config files for iMon -> MediaPortal floating around the net, but none of them is "official" so you just have to randomly try some and then tweak things yourself. Media Portal's key mapping functionality is also semi-broken, you can't access all the functions from keys and you can't make them context-sensitive.
Oh, I also found out Requiem needs to be run from the machine where you authorized your iTunes; apparently iTunes does some encryption using the MAC address of the machine. Also there's some weird thing with an "SC Info.txt" file that you can search about if Requiem gives you trouble. It also makes zero output so it's hard to tell when it's working or not, and it just crashes if you give it bad args. But it's still the only decent un-DRM solution.
If you want to make an HTPC and have it Just Work you probably have to go all-MS. Buy a Windows MCE Remote from MS, use the IR receiver that comes with it, disable the IR in the case, and just use Media Center as your player, and put all your content in My Documents. Don't bother trying to make your case's LCD or IR work and just go with what the MS stuff can do and it should all work okay. While I found MS's Media Center to be ass for music, it does seem pretty nice for TV if that's what you want.
Anyhoo, the HTPC with Media Portal is now sort of mostly working. The LCD doesn't work yet, but fuck it, it sucks anyway. AMD's Cool & Quiet doesn't seem to be working, but fuck it, it's cool and quiet enough already. UltraVNC does work with MediaPortal so I can remote that way. The default MP skin is ugly and the other skins I tried are broken, but whatever, fuck it.
In theory MP is open source so I could build it myself and fix the things I don't like. I've never had success with building one of these big messy open source apps before, though, so I'm very scared.
A few big todos remaining :
1. I've got a big problem with the music mirrors on our laptops. Ali and I both have our old copies of music and we may download new stuff in the future; I need a way to get that stuff into the share easily. The problem is I've already renamed a bunch of stuff on the share machine and deleted our duplicates, so I can't just xcopy. Yucky bleck.
Really the whole interface with exposing the share to her iTunes is yeck. When she gets new stuff I need to copy it to the share, and possibly change the file names to regularize because fucking music file names are randomly broken (the same band will be given slightly different names - for example you would have "AC-DC", "AC DC" and "ACDC"). I need to remember what was copied so that I don't copy it again. To expose the share, I need to get it into her iTunes, but without duplicating the stuff she has locally. And when I add new stuff to the share I want it to get into her iTunes quickly without doing a full dir scan. Ass ass ass fuck. There are some apps that do some of these things - Dupe Eliminator and iTunes Library Updater but they're both ass in various ways. I've used iTLU on my local machine and it's slow as all fuck, and you have to manually run it to get your new music in. Bleck, better solution is needed.
2. I want a figure out a way to just send playlists from other machines. I want to be able to browse the music share from my laptop and pick some files and click something on my laptop and have it start playing on the HTPC. The HTPC remote interface is okay for playing one album, but if you want to put together a playlist you really want your computer with a desk and a mouse. I'm sure I could do this pretty easily myself if I could write a Plugin for MediaPortal. This is relatively easy if I'm making playlists in WinAmp on my machine that directly refer to files in the Share, and the just sending the M3U file over the net to the HTPC machine; I'm sure I could rig that up pretty easily. It's much harder to rig so that Ali can make playlists in her iTunes and get those to play; for one thing her iTunes may refer to local copies of a song that is also on the music share. Like I said before there's still the possibility of just beaming your audio out from your machine to the HTPC, but that's not ideal because you'd like to be able to fire a playlist off and then do other things on your laptop and have the music keep playing. You know, like a fucking CD does.