Hey all,

In efforts to expand my options for creating riffs / melodies and et cetera, I've decided to learn major and minor 7th arpeggios. Now, the problem is I don't really know when they are useful. So far I play in key (mostly using the pentatonic scale over whatever chords are being played.) Would the 7th arpeggios only be useful when playing over 7th chords?

That is all... I think. Also, I'm not necessarily interested in sweep picking and shredding at immaculate speeds, only, you know, pleasing sounding stuff.

Arpeggios are useful when you want the sound that a particular arpeggio makes to be in your music.

And yes, a 7th chord arpeggio IS a 7th chord, just broken.
Oh yeah.

Quote by hildesaw
A minor is the saddest of all keys.

EDIT: D minor is the saddest of all keys.
arpeggios whether they are 7th, 9th or whatever are meant to give another "flavor" to your lines. They are very useful in a jazz context to play the chord tones but they're just as useful in any other context depending how you approach them. It also helps you to learn your notes and patterns around the neck.
My gear:
-Ibanez JS 6000 Custom w/ 11-48 gauge
-Ibanez FGM 400BB w/ 10-46 gauge
-Peavey 6505 2x12 Combo
-MXR Phase 90
-Boss DD-6 Digital Delay
-Morley Wah/Volume Pro Series II
-Boss CS-3 Compression Sustainer
-Gator G-Bus 8
-Xotic BB Preamp
I highly recommend that you learn the major scale in addition to the pentatonic scale. You'll learn how chords are created along the way, and with that, arpeggios and key theory.

Randomly learning 7th arpeggios with no background is a pretty odd choice.
And no, Guitar Hero will not help. Even on expert. Really.
I know arpeggio / chord theory as well, but just haven't used them other than making a chord shape and hitting the individual notes, which I know is using arpeggios, but I was wondering, I guess, if there was a better way to go about using them...
So I've decided to keep up with learning them 7th arpeggios while also learning the chord shapes throughout the neck in various keys and what not, knowing all the places to play my wonderful Am chord and those that fall under its spell, and then being able to diddle with the arpeggios in there as well. I'm on my way, friends. On my way.
All good, learn to use the edit key in the future.
And no, Guitar Hero will not help. Even on expert. Really.
jordanZZ by all means learn 7 scales. But learn the major, minor, pentatonic, and modal scales too. If you are playing lead, you will want to learn all of them so you can intersperse different lead lines with something new and flavorful, you know, like what happens with modal scales. They are totally awesome in leads. You can certainly play a 7th arpeggio scale with the 7th chords played under, but you can also play 7th arpeggios with the root chord (like an E7 with an E chord) under, or any other chord in the root chord scale, it will still work pretty well. Use your ear (and your guitar buddies ears) as to what sounds good.