I will try and include in my 5 one common card and one that is peculiar to the design or not as often seen. I'm poaching the scans, mostly from Ebay, and do not know how to control their size.
1. Guidry--already shown. Great shot of Gator issued during the best season I can recall from a pitcher.
2. Murray--already shown. Love the way he's looking right at you and the rookie cup.
3. Thurman Munson. The classic backstopper looking like a leader.
4. Sparky Anderson. I like the design concept of contrasting player vs. manager. Skipper of the Big Red Machine during this time.
5. Roy Howell. I picked this as my common man for 1978. I love cards where the photographer beautifully frames the subject, the background captures part of the baseball experience (e.g.the ball park and not some washed out non-descript blurry background) and the player's gear is prominently displayed--here the logos and colors of a team in its infancy.
FWIW, I do not regard the 1978 set very highly. I hated it when it came out for being lazy in design--a script team name? Lots of muddy photos too, although every Topps set still has its gems. It has grown on me more over the years though, but is still my least favorite set of the decade (as if anyone cares).