A lot depends on if you're doing analog or digital recording. I like to run tape a bit into the red but for digital you generally want to keep away from it. Some digital software that has 32 bit float processing can handle the individual tracks being a bit hot as long as the mix bus is below zero. Some folks recommend recording around -6 so that you have some headroom for eqs and processors. A lot also depends on your AD converters. Some cheaper converters seem to sound a bit better with a hotter signal.
The best thing to look at is your calibration level, if say your soundcard was calibrated so that 0dbfs=+16dbm, if your going to record neer 0 in that situation do you really wan't your equipment running that hot, just to have the levels sit at -6 to -1dbfs your pres going to be running at a +10 to +15dbm level and eating up your pres headroom. A better way to lookk at things would be run your equipment at around 0 to +10dbu so you won't be running your pre that hot giving that your DAW levels in that calibration level would be from -16 to -6dbfs which gives your pre and DAW a little headroom incase of peaks also you might not clip your plugins internally either cause its got some headroom too, this isn't as bad with floating point but is very evident with fixed point math (internally clip the Q10 plugin in TDM and you will hear horrible results).
Yes, in DAW "world" I am learning it is different.. I like to run things around -6dB because at levels lower than that I have a lot of trouble getting the 2-bus up to -2dB on mixes without running the channel faders up above 0dB. I can hit -2dB peaks but not on average, which is where most modern mixes seem to be sitting. Many mic pres choke if you try to feed the DAW to even -6 with them, running out of headroom. One pre that I have come across that has lots of juice for the DAW is the Great River MP2NV. Being a true 3 stage (amp) mic pre of the 1073 type, it has well over 60dB of gain which is what it seems my DAW really likes. I can get plenty of signal into the workstation while still having lots of headroom in the pre.. I have found it working very well for electric piano and keyboards, clean, clear, loud, no distortion.. yuuuummm!
so where can I find the calibration data of my soundcard(M-Audio Delta 410). I am going to go look on their website to see what I can find over there.
Another question, it has been said that I want to run at lower levels to leave headroom for head room and other effects. I was under the impression that it was better to cut frequency than to boost. If I am cutting, do I need the extra headroom??
True, and this is something that needs to be considered. But there is also a whole lot of older digital gear and I'd even guess way more older gear in use that is over 2-years old where the old rules still apply. And even the new crappy digital gear can be worse than the older great digital stuff. Newer doesn't always equal better and even less so when it is cheap and new.