I think Flac was great back when Hard drives and storage was an issue, It saves about 25% of the file size and they do certainly sound good. But now we really shouldn't be worried about file size anymore. I like Flac for downloads if I'm going to play them on the computer. 
But- 
Flac won't play on most MP3 players and car stereo systems so MP3  is a little more universal. 
 
I stay with working from start to finish with 44.1 as my music is not going to sound any different at a higher clock rate. My studio is basic stuff so I'm happy with that. The songs even seem to sound about the same after I upload them to sound cloud, clicks or reverbnation. I upload at 160 KB because of my limited bandwidth. 

Actually Flac is being more and more widely adopted. It plays fine on android devices, Neil Young's pono device recently adopted it, but Apples hates it (no surprises there) and wants you to use their proprietary ALAC format instead (I think you can get apps for it though). The great thing is, that it is not proprietary, and I disagree the more space I get on my hard drives or mobile devices for my music and other data the better....
 
 
BTW I've recently started recording on 48khz as I'm realising that music ends up more and more on videos formats. Craig swears you should record at 96 there's another thread for that:
http://forum.cakewalk.com/Remember-that-96K-TH2-thread-I-Just-had-my-mind-blown-bigtime-m3046633-p4.aspx
 
 
Cheers...
 
Flac support:
http://en.m.wikipedia.org/wiki/List_of_hardware_and_software_that_supports_FLAC
 

FWIW I'm always fond of pointing out that MP3 is not a data compression technology, it's a data omission technology.

Ha! :)

I think the consensus from that 48/96 thread was that it may increase quality especially for softsynths that don't have an oversampling mode. So if your computer has no issues with the increased CPU load and file size it's a good default setting. However, 48 or even 44.1 is fine if your synths do have oversampling or if there is no difference for that synth. So "know what you've got" is a good rule of thumb I guess.

I have been considering switching to 48 too for the same reason Alex mentioned.

If you use Dimension Pro you're probably using FLAC files already without knowing it. But they're converted back into wave files when you play or render them.

Yes and a lot of the Session drummer samples are flac

Sanderxpander
I think the consensus from that 48/96 thread was that it may increase quality especially for softsynths that don't have an oversampling mode. So if you're computer has no issues with the increased CPU load and file size it's a good default setting. However, 48 or even 44.1 is fine if your synths do have oversampling or if there is no difference for that synth.

That's a very good summary except some plug-ins also benefit from 96 kHz operation. I still run at 44.1 kHz most of the time but if needed, for soft synths I'll create a 96 kHz project, bring in the MIDI file and soft synth, render, then bring the audio into the 44.1 kHz project. The "96 kHz goodness" gets baked into the audio range, so it still sounds better at 44.1 k Hz.

You mean those plugins benefit from a softsynth running at 96KHz? I remember there was also some discussion if the "mellower highs" weren't simply a result from SRC-induced LPFing.

I'd be interested to hear if you have specific plugins that work better at 96KHz.

The main types of plug-ins that benefit from 96 kHz sample rates are dynamics processors, especially ones with lookahead. Unlike synths, though, in my experience the benefits tend to be more theoretical than audibly obvious.
 
However regarding specific plug-ins, there was a thread on Gearslutz a while back (I think it was referenced in the original 96 kHz thread) showing many plug-ins (and naming names) as having aliasing problems that could be reduced by running them at 96 kHz.