My wireless acts up all the time... The only game i play online is battlefront 2 so bear with me. When I turn on the game, it usually takes 1-3 seconds to sign into xbox live (which seems fast to me), then when i click optimize game or whatever it is, it finds all the games available (usually takes 8 seconds or so which seems fast), but then when i play games, i get the conncetion icon in the bottom of the screen a lot and when i make games of my own, people rarely join in. That being said, we have the fastest cable internet in the area at 64mpgs or whatever it is. We download at over 300K off the internet and i would think that we could host fast games at my house but it doesn't work out like that... why?
Are the games you are joining run on dedicated servers? also, wireless gets slower the further you are away from the base/router. try moving your xbox closer to your router if possible.
What is your connection exactly? Your original post left me confuzzled..... Does XBLive have a bandwidth tester utility? If so use it and post that here....You need some serious power to host, not the cheap DSL like me :)