I don't have many childhood favorites that I think still hold up, except for Douglas Adams (speaking of who, Eric, have you gotten your hands on the old Infocom games? "Bureaucracy" is...well, I liked it). I wasted more than a bit of time and money on, say, Star Trek novels that I wouldn't be caught dead with, today.
Since then, I haven't looked at much recent material. In fact, the few modern novels I've bought, I would recommend against, rather than for, for the most part. William Gibson? Neal Stephenson? Eh. (Though I thought Gibson and Sterling's "Difference Engine" was decent at the time.)
No, wait. Let me edit my message to be mroe direct. Avoid "Cryptonomicon" at all costs. Imagine any faults you could ever find with Tolkien, but add more computer jargon and set it on streets that seem even more excessively described because they're places you've probably already seen. And his characters talk about things I'd really rather not hear about, to be perfectly honest.
Where I've been doing most of my reading has been the public domain, mostly via Project Gutenberg and similar sources.
The one major exception to that has been Philip Wylie. He's a strong bridge between the "scientific romances" and the comic books in more ways than one. "Gladiator" (public domain) is Superman without the optimism. "The Savage Gentleman" is darn close to Doc Savage. "The Murderer Invisible" is part HG Wells and part Arkham Asylum. "The Spy Who Spoke Porpoise" isn't as nifty as it sounds, but is still fun...Anyway, I haven't gone in full pursuit of his work (for example, "When Worlds Collide" has been on my shelf gathering dust forever), but what I've read has been worthwhile.
Through Gutenberg, though, I've discovered quite a few interesting authors that seem otherwise forgotten. Paging through the list, I see a few...
Laurence Mark Janifer is one where I have only read a couple of the stories, but they have a light feel to them and examine some interesting ideas.
I don't know if he's done anything other than what's available, but Roger Kuykendall has a nice, wide range. "We Didn't Do Anything Wrong, Hardly," is the sort of story I'm surprised we don't see far more frequently.
Will Jenkins ("Murray Leinster") has become a favorite of mine. Quite a few outlandish ideas floating around that seem to have inspired more than a bit of Golden Age DC's work as well as more modern writers like Roy Thomas.
Abraham Merritt isn't particularly good, to be honest, but the stories move fast, and the scope is always enormous, which is appreciated.
H. Beam Piper is probably the gem, and I'm really surprised his work isn't more widely known. Or maybe I'm not. After all, it doesn't make much sense for a company to make a big deal about stories they don't own. But I don't think I've read anything from Piper that wasn't excellent.
Cliff Simak...hey, he might be the one I like that people have actually heard of!
...And now that I've paged through the list, I see that they've added a lot of new stories. So if I vanish for a few weeks in the near future, that's probably why...