If you get your guitar tone before going into the recorder (as opposed to using an amp sim live) then there are many USB interfaces offer true zero latency input monitoring with simple front panel control. Even interfaces with DSP input monitoring can be pretty fast.

If you need to use the computer in place of pedals and an amp then latency will be determined by the computer's ability to process. Similarly with MIDI, it's how fast the computer can play back the samples. The interface itself is not the major source of latency once you force the signal to pass through the CPU.

Thanks for you reply, I do rely on realtime Soft amp sims a lot and in the past when I had a slower PC with latency above 7ms it was almost impossible to record something tight&fast with more than 3 guitar tracks,so for me latency is everything... I wondered if any users here have USB sound cards and if they have any issues with Soft sims recording...

If I were you I would choose PCI or Firewire cause they usually have less latency
BUT one sound card that I really love is the RME Babyface.

It's USB, has great Analog to Digital Converters and low latency :)

I think that you'd be fine with USB 2.0.