Beast Wars: Dinobot, Blackarachnia
RiD: Sky-Byte
AEC: Hot Shot
Bayverse: Blackout (having the honor of being the first Transformer to appear on the big screen)
Animated: Bulkhead, Lockdown
Others: Sunstorm, Drift

 

Well I don't know if Animated characters count since they are technically the same characters as G1 just a different incantation.
SO if it counts I would say

Animated Lockdown (original character)
Animated Prowl
Well....pretty much all of Animated (Blitswing was hilarious)
Animated and the movies are the only thing I've seen post G1

So movies:
Barricade!
The twins! (didn't say I liked them, but they are famous)

 

Dinobot
Waspinator
Animated Lugnut
Animated Blurr
Movie Ironhide
Movie Ratchet
Movie Prime
Animated Seeker Clones

 

For me...

BW Dinobot, Waspinator, Inferno, Megatron, Rattrap
Animated Starscream
Movie bumblebee, megatron

 

Thinking mostly in terms of characters with life/fan presence beyond their orginial media depictions:

-Almost everyone from BW/BM, but especially:
* Optimus Primal and Megatron - for developing new archetypes for the leader characters.
* Dinobot - made the hall of fame, so he must be doing something right.
* Rattrap, Blackarachnia, Waspinator - popular enough to be re-imagined for a different series.

* RID Scourge - for popularizing the 'Black Convoy/Nemesis Prime' concept.
* Sideburn & Sky-Byte - weird enough to be interesting and popular.

* Hot Shot - probably famous more to "JAAM" fan-attention than any other reason.
* Rosanna - same answer

* Movie Bumblebee - for shifting public perception of the character from "weak but friendly guy" to "Autobot Snake-Eyes".

Animated: Similar to Beast Wars in that most characters are memorable, though colored by many of them being re-imaginings of classic characters.
* Prowl, Ratchet, Blitzwing - Adding new ideas or depth to characters, which likely will show up in future versions.
* Lockdown, Lugnut, Bulkhead - Original characters that already are migrating into other styles/toy lines/series.
* Sentinel Prime - Hopefully we'll see more 'antagonistic' good guys in the future. More 'Frank Burns' or 'Dwight Schrute', if you will.

 

Movie Barricade. Evil Police car? How could you not love that?

Movie Twins. Girls seem to like them.

I actually don't like Dinobot or Lockdown. And I HATE Rattrap. I'll concede he's a good character but his voice grates something fierce and the buck teeth in bot mode are just naff.

The most famous post G1 characters are going to be the Movie casts. We may not like it but they have more exposure than any other version of TF's.

I will say Bay took my least favourite members of the Ark crew after Wheeljack - Prime and Bumblebee, and actually made them cool. Shame he butchered Ironhide. Movie Ratchet deserves more love. Great voice.