If you don't have an HDMI receiver, there's not too much reason to use it for video switching if your TV has enough inputs for everything. The only trouble you might run into is with the PS3. I don't think you can run HDMI and analog at the same time.
If you want switching in the receiver, the best way to go might be something like this:
Wii - component and audio to receiver
PS2 - component and audio to receiver
PS3 - component and audio to receiver (but this won't get you Blu-ray, see below)
HD box - HDMI to tv, digital audio to receiver (I'm assuming you don't have more than 3 component on the receiver)
Component from receiver to TV.
Use digital audio into the reciever from any source that has it, either toslink or coax. This way, your receiver will do all the switching except the HD box.
If you hook the PS3 directly to the TV via HDMI, you could use the TV audio output into the receiver. Hopefully the TV has digital audio output, but even then, some TV downmix the digital audio to 2 channel for output. The PS3 is going to mess up your connections, since it won't do digital and analog at the same time.
It may be time for an HDMI receiver upgrade???