IMHO midrange bikes are the best. I have a $350 Giant hybrid. I average about 18.5 mph over an 11 mile commute, including 4 miles of gravel road. I've looked at more expensive bikes but I'm not convinced I'd gain much. I'm never going to be a speed demon, and my bike has only ever failed me twice and made me walk home, both of which were entirely my fault for screwing it up, and would have happened even with a $3000 bike. I've got 12,000 miles on it right now, and all I've had to do was rebuild the rear wheel (the first year, it was crap) and replace chains, brake pads and tires, plus the RD wore out after 10000 miles.

I don't think that you'll get much more UTILITY out of spending more than, say, $750 on a bike. That puts you into a pretty solid and durable bike. If you're going to rely on the bike for something like long, unsupported tours, I'd put that up to maybe $1250 for something like a nicely-equipped LHT.

However, bikes are like telescopes or any other hobby; you can get caught up in always wanting something a little better. Just realize that there's no end to that. A guy with a $2000 can convince himself that he really NEEDS a $3000 bike, probably easier than a guy with a $300 bike can convince himself that he needs a $1000 bike.

Bailing out of the high-end equipment lust treadmill is very helpful. Look at purchases objectively. Maybe that $3000 bike really will increase your enjoyment. If so, and you choose to spend your money that way, then go for it!

Oh, and look for used bikes. There ARE people caught up in the upgrade treadmill, and you might as well get their castoffs.