Jesse Screed
Hey V L V, I think it is very cool that you are stretching out with your playing.  It has been very informative reading all the posts about modes and chords and theory.  I can't wait to hear your next song on the forum.  I hope you use some of what you have learned.

Yeah, it's interesting isn't it?  What's really cool, is that after 30 years of playing an instrument I feel like I'm rediscovering it all, which has lit up my riff writing and I've stepped up my game a bit.  It's really exciting, actually.  
 
I can't wait to start laying tracks.  Got a few months to go before I have my studio space...

markno999
Voda,
 
The G chord with F# in the would be a Gmaj7,  a G dominant 7th has F instead.   The dominant 7th is generally a leading chord as the sound is pushing to resolution.     In Sleepwalk, the G7 is leading to the C.   Maj7 chords have a different function, usually.    
 
You can absolutely play a G7 in the key of G.   In that case the G7 is generally going to be pushing to the 4 chord, or C.
 
Once you get these sounds in your head it will make a lot more sense, theory alone can be confusing.
 
Regards

That's interesting, been trying that out. Mind you, I'm now having trouble stopping myself playing a Bm instead of a G7, they sound the same to me 

James, of course Bm would work as well, just make sure everyone else is playing Bm instead of G7. F against F# generally doesn't sound too good:) You could also just play G/B instead of the Bm and not clash with the people playing G7.

markno999
James, of course Bm would work as well, just make sure everyone else is playing Bm instead of G7. F against F# generally doesn't sound too good:) You could also just play G/B instead of the Bm and not clash with the people playing G7.

Oddly enough, the explanation from Quora read pretty well but this bit here seems ridiculous, ha ha:  "Basically, no matter what chords are in your given key, you can add a dom7 chord a fifth away from every one of those naturally occurring chords to your chord pallet. It only wont apply to diminished chords that exist in your key."
 
Lucky for me, I actually can't stand the dominant 7th sound.  I won't be working too hard to unpack this, but it is interesting, nonetheless.  
 
 

Voda,
 
I agree with you, the Dom7th can be a super cheesy sound, but it can also be about context.    For example, a Dom7th is a predominant sound in Pink Floyd's Brain Damage, that is a pretty cool song.  
 
Or take a song like Something written by George Harrison.   the progression goes C, CMaj7, C7.  In this case the C7 sounds pretty cool and is pushing to the F that follows. 
 
Lot of rock and pop music uses dominant 7th sounds for descending lines.   Ex, you are playing A to F#m and your bass player sticks a G in in the bassline between the A and F#m, that is A7 with the dominant 7th in the bass.
 
I think it helps to study these things in music you like or listen to rather than focusing simply on music theory.   Theory and be mind numbing and paralyzing.   I know people that have problems soloing because they are so focused on which mode they should be in, that they are either not playing musical sounding solos, are playing boring scales, or are just lost.  I am not saying not to study theory, but take it slow and apply it to where you are and what you are interested in, then you will retain it and use it going forward.    Main thing is not to get discouraged with theory because there is a lot of theory out there that is very poorly presented. 
 
Regards

markno999
Voda,
 
I agree with you, the Dom7th can be a super cheesy sound, but it can also be about context.    For example, a Dom7th is a predominant sound in Pink Floyd's Brain Damage, that is a pretty cool song.  
 
Or take a song like Something written by George Harrison.   the progression goes C, CMaj7, C7.  In this case the C7 sounds pretty cool and is pushing to the F that follows. 
 

 
Two of my favorite artists and one of my favorite all time songs.  Point taken, my friend.