Poliwrath is indeed god, as nothing says fuck you like it. ;D
Wow... People aren't keeping this thread updated. Time for some info.
As you'd expect, HGSS's September release in Japan has had a shitload of coverage by serebii, and since I'm too lazy to do anything but get a link, go here for epic spoilers.
For more important things regarding HGSS that justify more than a link...
While of little concern of more than aesthetics, every single poke will follow you, if it's at the head of your party. Furthermore, their shininess will be retained. Wewt!
Headbutt is back with avengeance, allowing you to headbutt every single tree in the game for pokemon! In the aforementioned link, you should be able to find more details regarding this, including what headbutt pokemon are found where.
There will be a Celebi event for HGSS in the future! This will unlock a special event in HGSS, which you can find details here. Beware of the major spoilers.
Since I feel this deserves it's own link, this link details the locations of all legendaries, how to get them, and any other details such as level, soonest you can get them, etc. Yet again, spoilers.
HGSS indeed has the Battle Frontier of Platinum! ... Without any new features, sadly, but hey, better than a battle tower.
HGSS has new areas not present in GSC! For some spoilers, here another serebii link.
The Safari Zone that was never utilized in the original GSC is now here! I honestly can't wait to explore it. Located West of Cianwood, it's available before Kanto, thank god. For details, here's a link.
The Pokethlon: what the hell is it? Find out with this link. ... You know the drill, spoilers.
As expected, the PokeGear has returned. For details and some pictures, here's a link.
I didn't expect this, but it seems Pal Park's back in HGSS. Better yet, the 6-a-day limit is gone! For details, go here.
While not all-too relevant to HGSS, a wi-fi Shaymin event is going on, until November 8th! I've already got my Oak's Letter, so I'd get it ASAP.
OH MAH GAWD. Two events in one posts? Win. Yes, it's what you think it is; the US Toys R Us Arceus event has been announced! It starts november 7th, and ends November 15th. You've got a week, so if you miss this event, you've got some problems. You definatly shouldn't miss this event; it unlocks the special event in HGSS. For epic spoilers on the special event, click this link.