For those of you that venture South, try the fajitas at the Slab Shack on Manchaca Rd. (about 1 mile south of Slaughter). They specialize in BBQ, but they throw some fajitas on the smoker as well. Danm! they taste good.
Its right by buttercup creek. It is in the shopping center where the pet store and the used furniture store are. It is all the way in the back where Mr. Gattis (spelling) used to be
Pappasito's fajitas are by far the best. Chuy's has incredible tortillas though. For an authentic experience, try anything on South Lamar, the brighter the colors, the better.
Iguana Grill? If you want to pay an arm and a leg for some food and a drink, then the Iguana Grill is the place to go. Actually, anywhere out on the lake is high priced.
As for the best tasting fajitas, there are many places that deserve to be mentioned.
Yes, Pappasito's has the best tasting fajitas.
Some other places worth mentioning are :
Enchiladas Y Mas
Hula Hut (Shiner Bock Fajitas)
Trudy's
But you always have to ask for more condiments and extra tortillas.
I will agree with a lot of guys on this posting and say that you can never go wrong with the HEB marinated fajitas over an open flame on your own grill with a nice cold brew in one hand and some tongs in the other.
DAMMIT I'm hungry now. I guess it's time to fire up the old pit.
On kinda a weird/special nod. The UT Club (on East Side of Stadium) and during game days serve some of the most delicious and marinated fajitas I've ever had. I've run the gamut on Mexican food restaurants in Austin, Houston and San Antonio...and the UT Clubs are def. in my top five.
Pappasitos should only serve fajitas--and only chicken fajitas at that. Great homemade tortillas, tremendous tender chicken, the butter sauce to put them over the top; and you can even get them with skin or without. I'm not a big fan of the warm salsa--if you could sneak in El Sol y La Luna's salsa (or any other suitable replacement) it would be fajita heaven.
If you want great enchiladas or breakfast then go to one of Austin's many unique and authentic places, but if you want awesome chicken fajitas then Pappasitos is it IMO.
Heeding the suggestion of unpainted on this thread, I tried Serranos fajitas at their Red River location.
I was very pleasantly suprised at how good they were. The meat was good quality and it had a nice trace of mesquite smoke in it. They were pretty tender and were thick cuts of strip steak the way I like it. They also had freshly made tortillas which is definitely a plus. I will definitely go back. Though not as good as Pappasitos, it is without question the second best in Austin. This location was much better than the one I went to in Lincoln Village near Highland Mall several years ago.
Mama Grande's on E. 12th Cooked in bacon fat by a woman who looks like she is made of the same. You can actually get the chicken sauteed with bacon. Screw the sour cream, this can come with a side of some strange kind of garlic flavored fat.
Lovin in a tortilla.