I've become a huge fan of Plastic Man since I started reading superhero comics in earnest about a year and a half ago. It's safe to say that of all the 'traditional superheroes' (costume, secret identity, ect.) he's my favorite. Now, mostly I've been concerned with reading Jack Cole's original Plas comics from the '40s, but I've recently begun raiding back issue bins and such for other appearances of the character.
In Cole's hands Plastic Man existed in a world somewhere between Warner Bros. gangster picture and Looney Tunes cartoon. Plastic Man's powers resulted in rapid-fire visual gags and he assumes a plethora of forms to accomplish his goals or to suit his emotional state, but while Plas is a prankster he's still a credible hero (much like Spider-Man after him), not a buffoon, like he's often portrayed as for the past few decades.
... which brings me to what I just read:
Plastic Man: On the Lam, which collects the first storyline of Kyle Baker's 2004 Plastic Man series and it is incredible!!! Baker amps up the cartoonishness to Ren & Stempy levels and adds a whole lot of meta and forth-wall breaking comedy skewering modern superhero comics (reboots, canon, power rankings, and Plas' modern status quo as the buffoon of the DC universe are frequent targets), but Plas retains his heroic qualities and there are a few moments amid the madness where the comic gets quite dramatic and even heartfelt. It also features a wonderful incarnation of the Justice League, who are presented as out-of-touch jerks.
Also, at one point Plastic Man becomes a blimp.
