You guys are crazy. There's so much cool stuff to do AFTER beating Red in that game. Like catching the Hoenn Legendary Pokemon (Groudon and Rayquaza in your case) and getting starter Pokemon from other regions. HGSS is the only game I know that can stay interesting even after beating the strongest trainer in the game. Just because of all the cool stuff jammed into the game. I really miss my Pokewalker...
Well my problem is that I've played my Emerald through dozens of times and I haven plenty of Groudons, Kyogres and Rayquazas from that. I also have plenty of 1st gen starters Pal Parked from my GBA games. I've played tag with Latios in my SS and caught Latias in Pewter City (event).
Done more of less the same on my HeartGold last run and I'm just sort of... just sitting there with 16 badges always and looking at the level curve... and then going "nope", moving things to save on my Platinum or SS before thinking up a new run on it.
Only legendaries that I've never had are Jirachi and Palkia... and Palkia is just that my first game was Diamond, with over 100 hours played before I moved everything to White, and I'm too lazy to go get it in Platinum.
My Pokewalkers are almost all the time with me since they're in my bag (they get steps there) or pockets during the days.