I usually run mine at 1024 buffer and at 96k. Gives the DAW room to breathe. I get zero latency because I monitor through hardware. This works for vocals, acoustic guitar and electric guitar. I only change it when using VST's for bass/keyboards, then to 64 or 128, works fine. I don't pay a lot of attention to latency figures because I have found that can be deceiving. My Focusrite 2i4 was exceptionally bad here, telling me 9ms when it was more like 20ms! I rely on my ears to let me know what is acceptable.
Thanks for that info, I am sort of over amp sims now though. I like the Jazz/Blues fenderish clean sound, a bouncy amp sound. Sims struggle with that, I did numerous sessions of over 60 tracks at a time testing out various sims (not the ones you mention). The best sound I came up with was from the $50.00 American Sound Joyo pedal I compared them too. There is also the workflow issue, I don't like fiddling around with ir cabs, mouse driven knobs etc. Using the pedals, I don't even look at the computer and I have real knobs to tweak if something sounds off.
I personally wouldn't monitor through software, first there is the latency issue and then, when you start loading the project up with tracks, plugins and VST's, your throwing all that at the CPU as well as asking it to provide perfect latency. Monitoring through hardware means those things are not going to interfere with your zero latency, your also not going to get the horrid clicks, pops, stutters and crashes etc associated with overloading your CPU.
To be honest, I don't understand the obsession with software monitoring. I must be missing something. Presonus takes the cake with it's Blue Z, Green Z and Native Z latency monitoring with it's drop out protection etc, then when you get problems you have to turn off plugins, freeze tracks and fiddle with dropout and buffers. Too complex and fiddly for me.
But again, I guess it depends what you are looking for, I am not sure what Clints needs are. If you are using amp sims, then I can see the obsession with low round trip latency. But if your a solo performer looking to record vocals, guitars, keys in a small studio etc I would recommend hardware monitoring over software monitoring. An interface that has:
Wall wart, not bus power
Min 4 XLR's in
Mic, line in and direct in (instrument)
Pads, selectable HPF and phase switch on each channel
DSP chip mixer (for hardware monitoring)
Smokin great quality Reverb
Compression and Equalization options for headphones/print to DAW
Good drivers that don't lie about latency and have low latency for VST's
Different manufacturers make interfaces that have some or all of the above and they can also be picked up secondhand on Ebay for not much.