I've got a Specialized Crossroads XP (a "hybrid" bike) that's served me well. It's beefier than a racing bike, but has narrower tires than a trail bike (700c-32 tires with Schrader valves, 75 psi). It's perfect for paved trails, I think. I bought it new about 15 years ago at a shop that was moving so everything was on sale.

We've also got a couple of recent Jamis bikes (a Coda, and a Coda Comp) that are similar, but they're more like straight-bar racing bikes (700c-28 tires with Presta valves, 90 psi). They're Ok, but I think they use lower-end components than the XP (which makes sense since the list price of the 15 year old XP was higher than the Jamis prices).

I've ridden a friend's Trek aluminum-framed trail bike and it was pretty nice. It was about a $1000 bike that he got for less than half that at a pawn shop. I think it would be tiring to ride on paved trails because the tires are so wide and knobby.

Since all the frames are probably made in the same handful of factories in the far east, and since the components come from a handful of manufacturers, there probably isn't much difference between the brands unless you're paying over $1000. Pick a price point and see what's comfortable. Check the want ads, too. There's probably quite a selection for low prices.

Higher end bikes have Presta valves which should be more air tight than Schrader valves, but they strike me as just being a pain in the neck because you have to use an adapter to pump them up with most air supplies, and they leak as much as Schraders in my experience.

HTH a bit. Good luck!