For some reason HDTVs and composite video signal "builds up" more lag than using component cables, add that a wavebird GC / wiimote (bluetooth seems more responsive than RF) and you got nearly 1/2 sec. of input lag. Some HDTVs like Sony tend to suffer, but LGs or older plasma tvs no (yes, but it isn't that noticeable). (depending on analog decoder?)
A wired GC controller fixes most lag issues
I use a Samsung LCD HDReady, plugged through component. I was playing Vampire Saviour in turbo mode Classic Pro Controller, and realised how much I was sucking. It just came up to my mind if it had to do something with input lag, threw a few weak punches and kinda seemed off. Plugged an only few months old unofficial GC controller, to realise it was already broken (I knew I had to purchase the official, actually at the time I was fooled thinking I had bought the official off ebay), left on d-pad, b button, jostick... it felt rusty after a few months not being used, yet it was smooth as silk to win the matches. Back to classic pro, and started to lose again.
I don't know about Tantric's emus, I haven't played such reaction demanding games, probably mario world and donkey kong on snesx9, sonic advance, on vbagx, before buying the component cables...
Sorry to jet, but most HDTVs totally suck for any kind of serious old-school gaming.
All the guys on fighting game forums such as Shoryuken know this - and wouldn't want to be seen dead training on an LCD/HDTV (granted, they're a bit nuts and fanatical - but they're still right in the grand scheme of things).
Also - videogame developers that make games for 360/PS3 have had to sacrifice 60fps for years now. This not only because the PS3/360 are seriously lacking in the CPU power department to begin with , butbecause they're worried that most people own HDTVs with sucky response times and they would get a barrage of complaints by people wondering why there is so much lag (when it's really their TV and the post-processing filter that is to blame). This is why you've seen such an onslaught of 30fps games with lame QTE gameplay - gotta give them people with laggy TVs time to press those buttons.
Also, they've stopped making rhythm action games such as Space Channel 5 and Parappa The Rapper on 'HD-ready' consoles for this same reason as well.
I made a post about this on a PS3 forum - forgive the slightly abrasive language - I have to wear different hats when hopping in/out of console scenes given the different ways people act in there -
http://www.ps3crunch...49441#post49441