I see you've already answered your question but I'll give you some of my observations...
For FLACs vs MP3s(320kbps CBR I ripped from the FLAC) I couldn't tell any difference with onboard audio except on high volumes. And after configuring the settings very generally in Foobar for them both the FLAC only seems to have slightly more depth on very particular songs. Especially based on the song's well.... particular sound.
With FLAC resampling, noise sharpening, and a few others things I can't recall off the top of my head there is a clear difference at just about any volume.
If I were you i'd do your best to get FLACs now because when the time comes when you can truly notice the difference you're going to wish your entire library were in it and it can take a while to build a nice collection and even more tricky sometimes to tag it correctly.
Fortunately for me I have a good bit of friends in different bands and they've all separately came to the conclusion of buying random music every two weeks and I have a great library system locally so I probably half my library is in the highest available quality.
Edited by Ryleh - 4/14/12 at 12:42pm