I kind of enjoy the discursive riffing writing Adams does...but I don't think the Hitchhikers books are the best example of that. Especially since, as you say, a lot of the jokes have become a little stale over the years (in that Monty Python-esque way, perhaps).

I think Adams is wonderful at pointing out the sheer absurdity of life, and how actually utterly amazing the things we take for granted really are. But that's something that's easier to do when he's riffing off stuff that are more directly connected to everyday life or the world as we know it, rather than the equally absurd and amazing but unreal universe of H2G2.

That's perhaps better seen in the Dirk Gently books - but Adams is way better in his non-fiction, as can be seen in And Another Thing, which collects a random assortment of essays on computers, and evolution, and money, and you know, just life, the universe and everything, right? There's plenty of fun to be had when we're making fun of

And Last Chance to see, the biodiversity conservation travelogue he did with Mark Carwardine, is one of my top 10 favourites of all time in both environmental and travel writing. Edutainment at its finest.