Oh, I definitely second Vonnie's rec, though those might be hard to find at a used bookstore.

If I were you (but then, I'm clearly not, given my bookwhoredom), I'd hit up Goodwill or someplace similar, that has books supercheap. They'll usually have some common trashy thrillers of the past few years for $1 a book or what have you--it's even cheaper than a used bookstore, but definitely not when you're looking for quality. But if you want stuff you can toss at the end to lighten your suitcase (or even not worry too much about dropping in the pool), they're excellent. There's usually several copies of stuff like "The DaVinci Code" or whatever--thrillers and trashy romances, which are good beach/pool reads. And then you can supplement that with a few more decent things for like, on the plane or whatever.

Teppy, you're going to totally love this-- Abby finally got around to reading her X-Men comics that I bought for her birthday. She just came bopping up to me and said,

"Both Nightcrawler and Colossus both decided to ask Storm on a date for a formal dinner at Banshee's castle in Ireland and they got cranky but luckily, didn't go all mutant on each other and then Banshee showed up at the dinner dressed like a stablehand which was weird because it was supposed to be formal, but he did it because he could since he's the lord of the castle and everything and it was really silly."

And yes, it really was one sentence. Delivered with word nerd glee.

Right on!

I like fantasy, mystery, spy fiction, etc.

Cryptonomicon

Also, Dirk Gently's Holistic Detective Agency and The Long Dark Tea-Time of the Soul

One of my favorite mystery series is the Nevada Barr Anna Pidgeon series. They are all set in various national parks around the US and are beautifully written, IMHO, but they are also great brain candy and easy reads. The first few books are relatively short, but they're all well worth reading. Track of the Cat and A Superior Death are the first two. The Wikipedia link above has them all in order.

I love Anna! I've been to many of those parks, or want to visit the ones described. For those I've been to, it is a lovely and familiar insight.

E Nesbit's children are pretty much the same, except their being in Edwardian England made them somewhat exotic to me. I was grateful to Harry Potter for encouraging publishers reprint books like those. Until Harry Potter, Edward Eager had been out of print for years.

This!

And you remind me - I just rewatched Labyrinth the other day, and was struck by the fact that my viewing experience was probably not that intended by the film makers; for me, the bit at the beginning when Our Heroine hikes up her skirts and runs home DOESN'T make it all mundane and unfantastical, it just makes it differently fantastical, because it's all so very American and unfamiliar still, the houses, the streets and all that jazz.

I like fantasy, mystery, spy fiction, etc.

Jacqueline Carey's Kushiel series could be a good bet? The swashbuckling adventures of a spy/courtesan/priestess in a sort of medieaval/fantastical alternative Europe? Alternatively there's Robin Hobb's Farseer trilogy? (And the Live Ships trilogy, and the Tawny Man trilogy?)

Nevada Barr is great, and if you can't find them all, I don't think they especially need to be read in order--I mean, there's a few details, but especially the earlier books, there's not a ton of personal stuff that carries through. The last few books, there's some, depending on which book, but even those, a few of them, there's not hardly any.

ooh! Vortex! the public library sells books - paperbacks are .50 and hardcovers $1 to maybe $5. They're books removed from circulation, contributions from people - the money goes to support the library. The main one downtown has a big Books Plus.

I've read most of the Vorkosigan books completely out of order (basically, in the order I found them.) They're all awesome, and readable without the others. They weren't written in chronological order either. So, basically... buy whatever you can get your hands on and read them in whatever order you want, is my suggestion.

As an additional suggestion, I just finished the entire "Twelve Houses" series by Sharon Shinn (the books that begin with Mystic and Rider) and loved them. They all have a romantic element - that's what she does - but there's also plenty of cool magic, swashbuckling, and political intrigue. In fact, I think that this series greatly improved her epic fantasy chops while sometimes underselling the romance. Which I was fine with.