Are DAWs good enough these days that we can totally get away with capturing hard rock/metal guitar riffs using mics?
You can go either way and still end up with a great, professional sound.
Mic your amp if:
Plug directly into an Audio Interface (like the Apogee Duet or MBox) and use a DAW if:
Check out FamilyJules7X's Recording Guide Series -- if I recall correctly, he plugs directly into the interface and edits all of his guitar tones in Gearbox which came with his Line 6 Pod, and then tweaks everything in Mixcraft - the end result is usually pretty gorram good!
Whether to DAW or not to DAW.
The key factor is how much tone are you getting with the current guitar/amp rig?
Many professional blues guitar players tell me that once they mastered their instrument, they understood that their tone was more about the amp and the guitar combination not just the guitar. The amp plays a big role for these guys. For many, they describe it as synergistic--that sure sounds like a 1960's thing to me.
If you have a vintage 1965 Fender Black Face Super Reverb (not the re-issue) or a vintage Fender 1959 Tweed Deluxe 5E3 (not a re-issue), and a Strat or a Les Paul, or a PRS, there is no way any DAW is going to give you that kind of tone. There is no tube amp emulation that will deliver the true tone of these amps including LINE 6. Ok, yes they have some very good emulation do dads out there, but if you do a blind taste test, you will find that there is no substitute for the real deal: Marshall Plexi, Fender Tweeds, Fender Black Face era amps and others have tone to die for when played with the right hands.
Recording these with a simple Shure SM57 is wonderful. However, if you are not in a recording studio where you can play these amps at the right volume for your desired tone, then a DAW or effects box sure looks good.
I sometimes rehearse with a vintage 1967 Fender Black Face Deluxe Reverb and a homebrew replica of a 1959 Tweed Deluxe that I can switch back and forth from and dial in clean to mean or in between. But I can't record this at home, I would have to go to a rehearsal space or studio. Often I am trying to come up with a guitar part in my apartment late at night, and it's headphones only, guitar through a Zoom pedal. But this does work. It's not horrible, it can be very good, but it would be so much better with a really good vintage tube amp that was biased and tweaked for the task at hand.
On the otherhand if you are a jazzer, clean is the thing, at least for most jazzer's. Even a solid state amp will be fine for this genre. So DAW recording is no problem here.
Although I don't play shred, many of the shred heads do just as well with their 'tone' with DAWs too. For some reason it's the heavy rock and blues players that really are tied to the tube amp sound, and few if any would trade their current amp/guitar rig for an emulation package even if it was free.
Simple answer: of course. I've been recording into DAWs since the early days of Cubase. Even with my current band we record all our album stuff through Cubase.
But this has always been the case, so I'm wondering if you are wanting some specific info.
You can't quite do the same things you can with midi, but if you treat your recorded audio as a wav or sample you can work with it.