Green’s Dictionary of Slang

all that adj.

also all of that
[SE phr. and all that, and all the rest of it]

1. (also all that and then some) just as described.

[US]Van Loan ‘The Bone Doctor’ in Score by Innings (2004) 361: ‘Ye–s,’ says Murph; ‘he’s all of that and then some.’.

2. of an object, excellent, wonderful.

[UK]F. Norman Guntz 28: The programme wasn’t all that.
Odessa American (TX) 17 Nov. 24/2: The Windy City, Chicago, is all that.
[US]Hip-Hop Connection Aug. 21: All That Something that is supremely good. As in ‘The Pussy’s All That’ by Red Hot Lover Tone.

3. (orig. US teen) of a person, in possession of all good qualities; often used sarcastically, thus to describe someone conceited; esp. in phr. think one is all that.

[US]R.O. Scott Gay Sl. Dict. [Internet] all that: adj. as good as it gets. (‘This Queen thinks she’s all that, and more!’).
[US]Eble Campus Sl. Apr. 1: all that – the highest in achievement. Said sarcastically.
[US]Simon & Burns Corner (1998) 113: Fuck them project niggers. They ain’t all that.
[US]Da Bomb [Internet] 1: All that: [...] 2. Superior to others; conceited. ‘Susie thinks that she is all that.’.
[US]Source Nov. 85: The Notorious B.I.G. was all that and more on the mic.
[UK]N. Barlay Crumple Zone 152: Marcus says that when you’ve been taken down a peg or two [...] you come to understand that, after all, as a guy, you ain’t all that.
[US]Teen Lingo: The Source for Youth Ministry [Internet] all that of a superior nature; wonderful or attractive. ‘That boy is all that.’.
[UK]Louis Slipperz ‘Spend It On’ [lyrics] Act like you’re all that.
[UK]Dizzee Rascall ‘Flyin’’ [lyrics] You could say I think I’m all that.
[US]Simon & Lehane ‘Clarifications’ Wire ser. 5 ep. 8 [TV script] Marloe was all that over Junebug called him a name.

In phrases

all that and a bag of chips (also all that and your bus fare home) [note that chips in the US are crisps in the UK]

(US teen) absolutely excellent.

[US]Baltimore Sun (MD) 19 Aug. Today 3C/6: Like people have been saying ‘all that,’ meaning something is really cool. But now they’re saying, ‘all that and a bag of chips.’ .
[US]Eble Campus Sl. Apr. 1: all that and a bag of chips – conceited, thinking highly of oneself; ‘Now that he has a new Beamer, he thinks he’s all that and a bag of chips’.
[Ire]P. Howard Miseducation of Ross O’Carroll-Kelly (2004) 213: Thinking he’s all that and your bus fare home.
[US]Nomad World [Internet] A few people even asked me if Bose made the unit. The Playdock is just absolutely ‘all that and a bag of chips’, a MUST HAVE for the music lover.
A. Tooms Rookie’s Playbook 70: This teacher thought she was all that and a bag of chips. She just walked around here like she was the queen of the prom.
give it all that (v.)

to boast, to show off.

[UK]D. Powis Signs of Crime 172: All that, giving it Bragging or showing off.
[UK]M. Newall ‘Sir Gawayne and the Grene Knyght’ in Indep. Rev. 26 Dec. 1: The grebo was giving it alle of thatte.