Books that are fun to read?

[Ezra]

The Doctorow starting point I'd usually recommend is Little Brother.

[AndaisQ]

Time for more recs, because I cannot be stopped.

Rick Cook's Wiz Biz, four books that I can find but I wouldn't be shocked if there's more: An intensely generic 1970s high fantasy world is at war with dark wizards and summons a fated champion; they get a programmer from Santa Monica. He figures out how to hack magic. It's a glorious thing.
Readability: High, if you like pulp. Helps if you've actually read the shit he's making fun of, or at least The Tough Guide to Fantasyland, which mocks it similarly but in greater depth.
Warnings: Kinda sexist, in an "isn't it clever how I'm being sexist in a sexist genre" kind of way. Similar mild racism. Occasionally very into itself, in a way that might be called either "self-indulgent" or "masturbatory".

Everything Diana Wynne-Jones has ever written. Please. I don't know if I can fully articulate how much everyone needs to read, and to already have read, Diana Wynne-Jones' full oeuvre.

Naomi Novik's Temeraire, 8 books, apparently still ongoing but I've only read 6: What if the Napoleonic Wars were fought on dragonback? That's all, pretty much. They're so good. I need to go through this again when I have any spoons and finish the series.
Readability: Moderate to low. The reading level is technically YA, but Novik is heavily influenced by the Master and Commander series, which is an agonizingly informative piece of historical fiction, so she's very, very, very into describing how shit works. Which is great if you like that kind of thing! If you're not in the mood, you may have a bad time.
Warnings: Wartime-typical gore, animal death (if sentient dragons count for that), social injustice both in that dragons are not citizens and in that it's the early 19th century and slavery is still a thing. I don't recall off the top of my head, but I think there are moderately sympathetic characters who oppose the protagonist on whether slavery is wrong, which is always super interesting but causes harm to certain readers. Also, it's the 19th century and some Brits go to Africa, so you can guess how that goes.

[Adelene]

Another one from the depths of my memories: Secret of the sixth magic by Lyndon Hardy. Appears to be the second of a trilogy, now that I look, but I've never read the other two and it stands on its own just fine.

[PlainDealingVillain]

The Doctorow starting point I'd usually recommend is Little Brother.

Little Brother is good, and has a sequel, though I haven't read it. I started with Down And Out In the Magic Kingdom and liked it a lot (Bitchun society is, well, bitchun). Someone Comes to Town, Someone Leaves Town is good too; the main character's father is a mountain and his mother is a washing machine, he'd really like to be normal, and it goes from there.

[PlainDealingVillain]

The Ravirn series (WebMage, Cybermancy, CodeSpell, two more) are enjoyable pulpy nonsense about the multiverse where the Greek Fates are sysadmins and magic can be written in binary (you sing it to activate it; most of them use sentient tools who can sing in hexadecimal, for efficiency).

Also, I second the Phule's Company series, those were great.

[Ezra]

Down And Out In the Magic Kingdom is an incorrect choice if you do not like to yell at the viewpoint character about their many terrible decisions.

[Adelene]

Also, I second the Phule's Company series, those were great.

Weren't they just?

Man, I kinda want Phule and Miles to meet, now. Can you just imagine the look on their collective superior officers' faces? :D

[Kappa]

Somebody wanna describe who Phule is and why this association with Miles? XD

[Ezra]

Well, they both apply an unorthodox military approach to pull off impossible victories and publicity nightmares.

[PlainDealingVillain]

Phule's father is the owner of the galactic weapons manufacturer Phuleproof. He is vaguely displeased by his father and joins the Interstellar foreign legion (the dumping ground of the armed forces), screws up, and is sent to head the dumping ground of the dumping ground because his dad is too rich for him to be court-martialed.

He then basically Mileses at them just to prove his superiors wrong, and proceeds to succeed at a number of ridiculously difficult tasks in extremely unusual ways, like winning a best-theme-park war and taking over Space Las Vegas.