Dark Iscariot... Come on dude... you can't actually expect anything like a real response to that question. There is no such thing as 0 latency. As my good friend Slackmaster2K said.
If you want an effects processor for your guitar, then go to a Music store, look behind the glass at the tons of effects pedals and buy an analog effects pedal.
if you are looking for an effects Plug in for a PC/Mac system you might be running, then you might try a sort of half way in the middle type thing and combine software with hardware and get the UAD-1 from Mackie. it is a power DSP card that will take the load off your CPU, plus it has several high end great quality plug in, one of which is called "Nigel" that seems to be killer for creating guitar effects.
And in the future...
If you have a question you have to be more specific. Slackmaster answered your question as best he could given the info he was given by you. but I get the feeling that you expect that we all just know what you are tqalking about when, we just don't.
Not trying to give you a lecture or anything. by the way... do you listen to "At the Gates"? I belive they are from Götenberg. Have you ever listend to any of these:
Last Days of April
International Noise Conspiracy
Fireside,
At the Gates
I fucking love Swedish music. Even ABBA fucking rules, if you think about it.