Hello Benno,
As a general rule, Shimano bits are good quality and will last and do what they're meant to do. Other bits are often as good, or better, but you 'can't go wrong with Shimano' mostly holds true. Bits that matter are things like the shifters (brake levers and hoods) and the front and rear deralieurs (I can never spell that 🙂). What's been suggested before remains true, testride everything you can. Try and get at least a 30 minute testride, and be prepared to swap seats a number of times. If you go to a good LBS (local bike shop) they'll let you swap seats, set the bike up for you etc, if they won't, go to another shop that will. You will develop a relationship with a good LBS that's worth having, so it's not worth putting up with bad service or misleading salespeople. Additionally, *never* pay retail. Every LBS will move on price. If they won't, see above re seats etc. at least 10% off their marked price is normal. They know you'll be back, so they won't sting you for price. Unlike the chain stores ....
FWIW, I have a 2002 Trek 1400 with mostly Shimano 105 bits (originally, most of the bits have worn out and been upgraded to DA or Ultegra), but the shifters are still good!) that's done 45,000km, and I'm heavy, and it's had no non-routine mishaps (ie: no bits have failed that wouldn't be expected to wear out). So Trek make a damn good frame. Pay no attention to the "made in <country>" stuff, a bored factory worker is no different in Taiwan or Wisconssin. I don't like compact frames because it's too hard to get your second bidon in and out, and long seatposts are, I think, more likely to break than short ones. I don't *ever* want to break a seatpost. That said, any roady around $2k-$3k will be a good bike and will do many miles of good service. Also, as a general principle, get the best frame you can for your money. Ie: if you have $2k and you can get an Ultegra equipt raceline or a 105 equipt cannondale or trek, get the bike with the 105. You'll replace the components over time, the frame, on the other hand, you're stuck with, so it's worth getting a better frame rather than a crappy frame with good bits.
Have fun treating your case of new bike fever, it's loads of fun!