Trek makes good frames. That one's a steel frame, right? It'll probably last forever. Components might not be that great, but change 'em when they break.
I think the obsession with bike weight has to be taken with a grain of salt. A lot of people on those sites are basically comparing Ferraris to Toyotas. If you start on a new ~$300-$400 Trek, then move on to spending $1,500-$2,000 a few years later, you're making an astronomical jump in the materials and technology put into the bike. There's nothing at all with the old bike you road a few years ago, but people forget that they've made a huge jump from something utilitarian to high performance.