Anyone have any good novel suggestions for an 18 year old guy?

Try Dean Koontz books. Nothing too deep and usually with a good ending (except the dog ones!)

These ones are autobiographical of sorts. But the authors give some insight into their lives, mostly travelogues...

Whatever you do don’t run

He died with a Felafael in his hand (John Birmingham)

Tasmanian Babe Fiasco (John Birmingham)

Don’t tell Mum I work on the oil rigs she thinks I play piano in a whorehouse

Touching the Void

Peter Moore:

No sh*tting in the toilet

The Wrong Way Home

The Full Montezuma

Swahili for the Broken Hearted

Vroom with a View / Vroom by the Sea

Brian Thacker:

Rule No 5 – No sex on the Bus

Planes, Trains and Elephants

The Naked Man Festival

I’m not eating any of that foreign muck

Where’s Wallis?

Sleeping Around

These are fictional wih male leads...

Holes (Louis Sachar)

Lord of the Rings / The Hobbit

Hitch hikers guide to the Galaxy (Douglas Adams)

Eragorn trilogy

Interview with a Vampire (Anne Rice)

Let the Right One In

Angels Gate (Gary Crew) (possibly more for younger readers maybe 15 yrs)

Virgin Suicides (Jeffrey Eugenides)

The Shiralee (Dárcy Niland)

Into the Wild (John Krakauer)

The 3 Muskateers (Alexandre Dumas)

At 18 I was always into the action novels that feature the most vile, evil villains imaginable, so I could experience the catharsis when the hero - whom I always liked to imagine was me - foiled their plan, and usually killed the bad guys so hard their descendants died from it. If that appeals to you, then try the Jack Reacher novels by Lee Child, the Mitch Rapp books by Vince Flynn, the Dirk Pitt bllks by Clive Cussler, the Jane Whitefield novels by Thomas Perry, the Nicole Shea books by Chris Claremont, and that standard stand-by, the Jack Ryan novels by Tom Clancy.

I was going to say Blood Meridian but it may be too bloody if you want romance. Check out Ian McEwan -- he does interesting psychological novels about relationships from a male perspective.