Hi,
I think I have been in a similar situation. You want to have a single remote control (hard button) and allow everyone to use the functionality of the equipment you have.
First of all I think Girder (
www.girder.nl ) is the way to go. It's free and you can adopt it to your requirements (functions) and the remote control you may already have.
Secondly you want with a single keypress that all the equipment you have is set as your family wants. Therefor not only IR reception but also output. A single button on the remote control and the PC handles everything. For that reason you were given a link to
http://people.a2000.nl/rwvgesse/ . This device is IRman compatible for reception AND can transmit IR signals to other AV devices. Secondly if you're able to build the device yourself, programming the onboard PIC is simple. Remove a jumper, run a program, add jumper and you're done. you don't even have to change any cabling.
I think I'm heading in the same direction as you, give a unique RC code to the PC and have the PC handle everything from that point onwards. Some notes however;
1) personally I (still) have some problems in programming the UIRT via a W2K machine (tried 4). Under W9x or ME it works without any problem. So after you build the device, use a W98/ME based PC to program the PIC. It's really simple
2) I have not yet been able to get the transmitting led's to work yet. I believe this is because of a failure from my side. The supplied software for the transmitting part really fits in the user interface idea from Girder. I think it's easy to use, but you will need to 'play' a little.
3) This refers to my last part. You have to 'learn' Girder. Personally I think it is the most versatile program to control any Windows application via normal (existing) remote control. You must however do some 'programming'. There are 2 steps to make;
3a) First learn the key YOU want to use for a certain function, to initiate the Girder activity. This is very simple, go to the desired function, press the 'learn' button and then the button on your remote control, you or your family wants to use.
3b) Girder is using so called 'groups' for different applications. You can download and import these groups into your Girder directory for the programs you want to control. Now sometimes these 'pre-programmed' groups don't work the way. This is mostly caused because your using different installation directories or different versions. The easiest way to resolve this is to follow the 'structure' of the imported group and adapt it to your local settings. When you're able to do that, Girder is your and your families best fried. You can make it as personal as you want.
finally the forum for
www.girder.nl is in english

Typical dutch.
rgrds,
Wykat.