I got the book "Great Lego Sets" (DK always makes the best books like that, ya know?) for Christmas. At first I was miffed that Blacktron Message Intercept Base was the representative of the "Blacktron" line (cira 1987) when it was the "Renegade" that really stuck with me.
(Here's the video for that- JANBRiCKS has pretty good coverage, hadn't heard of them before.)
For my money, this is when Lego Design first start getting cool - this ship, with its asymmetrical design (probably inspired by the Millennium Falcon, come to think of it), swept-forward wings, and that distinctively Triforce-ish logo. (Not to mention the Pilots with their cool opaque helmet visors) Before this, I felt I could reliably make cooler designs than the original sets, years later I certainly couldn't, and this set represents the transition. (Also, this ship DID sort of make the cut in the book, on a special page about the whole history of the Lego Space series.) 2 years later they'd finally start making cooler windows (see 6781: SP-Striker vs Renegade's clunky yellow cockpit) but I really think this was the turning point.
Space Lego was always special to me - Lego is the best "CAD" kit kids have for good-looking solid 3D design (Erector and K'nex are superior in some ways, but everything looks skeletal and wireframe) - I mean now kids might have 3D printers and Minecraft and what not, but then, this was it! Also, besides my Star Wars- and Trek-fueled excitement about the future, I knew that today's Towns, Castles, and Pirates didn't have little round studs on every surface... but the future MIGHT - so in that way the sets were "more realistic".
Oh, and here's a history of lego bricks- the book had a page on the history of the bricks thmselves, but didn't really mention when the "tube" design in the mix Part 1 and Part 2
Also I had this grand slam Christmas Gift in 1984 - Robot Command Center - - LOOOOOVED those grabby arms
What this world needs is Studio Ghibli Lego Sets- My Neighbor Tortoro and Porco Rosso and Nausicaa especially.