Gold Bug is my favorite, although it might be first-encounter bias. Gain was excellent, but a little drier.

Richard M. Powers (http://home.earthlink.net/~…, not to be confused with the author of such excellent books as The Gold Bug Variations and Galatea 2.2) was responsible for a lot of the great covers of that period.

The important thing is not to read it *first*. The series is better when read in the order written, not internal chronological order (see also Narnia, Elric). Otherwise its glorious dementia is reduced.

Don't Read "Triplanetary"
The "first" book in the Lensman series, "Triplanetary," is actually a prequel, written after the rest of the series, and contains spoilers for all the surprises in the rest of the series. Starting with "First Lensman" is a much better idea.