Interesting thread here! For me it's worked both ways: DXing causing me to "discover" stations I would have otherwise never known about, and trying to see how far away I could hear favorite stations.
Let's see...what ones have I "discovered" through DXing? (From Port Alexander, AK)
-570 KVI Seattle, WA
-now-defunct KSRA 580 Petersburg
-620 KPOJ Portland
-something in Seattle on 650
-KNBR 680 Sacramento...although I'd heard of it before I heard it on the radio.
-KIRO 710...same thing...actually my dad remembers DXing them up here in the '80s. (a station he DXed that he liked)
-790 CFCW
-whatever the huge country signal from Canada on 910 is...(liked that one a bit)
-1190 KEX...liked that one...Coast to Coast, I listen to them semi-regularly.
-1300 KKOL
-1600 KVRI Blaine (IMHO, the strangest thing I've ever heard on terrestrial radio, though whoever mentioned the "bagpipe sounds" above would take the cake...
Stations I heard locally and THEN Dx'ed:
-800 KINY Juneau (but discovered CKOR Penditcton while DXing KINY)
-930 KTKN Ketchikan
-1230 KIFW Sitka
-1330 KXXJ Juneau
FM...
Through DX, my I remember my dad discovered KBOX 104.1 Lompoc, CA, all the way up in Atascadero!
-KRKC 102.1 King City, also heard in Atascadero...right on the fringe of their coverage, acceptable signal and I'd listen semi regularly...but it was definitely not a local by any means.
-there was something on 93.7 in Atascadero that wasn't local...might have been the KYNS translator but I don't think so...it was country, IDing itself as "Kiss Country". Anyone remember that? I'd love to know what it was.
-Not sure if he discovered it locally in the Morro Bay/Cambria area locally or in Atascadero first, (I can ask if he remembers) but 94.9 was KOTR in the late '90s and had from what I'm told a very unique rock/AOR/AAA format...my dad bought a yagi specifically to try to get them. I wish I still had that antenna. It's now KPYG AFAIK and is also a weird AAA/country-ish format. I don't particularly care for it, though.
-there was a 95.7 "The Fox" (might have been KPAT Lompoc, now a hip hop station), also audible in Atascadero.
-95.3 KXTZ...this is an interesting one...in '01 they put up a huge signal on 100.5 in Templeton, and I remember thinking it was weird you could, from Atascadero, hear them in 2 different places on the dial!
-96.9 KWAV Monterrey...this was something I DX'ed and liked, it was BARELY audible though!
-99.7 KESC Morro Bay...my mom found this one, it was classical. Definitely on the fringe in Atascadero, though.
I should mention it's been a few years since I left Atascadero so things may have changed. Every time I look at Atascadero in Radio-Locator I see "new" signals...it's quickly getting to the point of "if it didn't have a signal on it a few years ago, it does now"...in other words almost every channel has a station or translator or SOMETHING on it, thankfully many of them less than local, so DXing is still fun there.
Also, the house we were living in was at rather high elevation, meaning reception was especially good for less-than-local FMs. Many that you would never hear at lower elevations came in clearly there, or clearly enough to be listenable.