Good to hear you're coming back to your senses
Best thing you can do is test ride as many bikes as you can, at shops, at races too, where some manufacturers usually have demo bikes to ride.
Likewise - welcome back to biking.
Having spent time helping a couple of friends into bikes, I completely endorse RDV4ROUBAIX's comments.
I'd just add the following words of wisdom/opinion/bull**** (delete as applicable after you've read this).
Get ready to hear about as much bull**** being talked to you as you would during your average electoral campaign. The two main culprits are the:
- "if it's not in my shop it's crap" assistant - they can't see past their own brands and will run down everyone else's product. The more different it is from their stock, the worse they will tell you it is. Always ask for reasons for their opinions and watch for when they squirm or whether their reasons make sense. Still check out the other product yourself, of course.
- "16 year old know it all" assistant - not necessarily 16 and actually a strange mutation of the weight weenie type breed. If it isn't carbon, with titanium water bottle bolts, two and a half spoke deep dish wheels, and double overhead doo-hickies, it's a piece of crap. Best thing that I've ever heard from one of these types (who was trying to sell me a bike equipped as such) was that flat bars on a MTB are gay! Who'da thunk??!! Handlebars have sexual orientations! (So caress your bars a little next time you ride - 'cos bars have feelings too ...)
If you've been away from bikes for ages, you're a prime candidate for the "you absolutely need ...". While there have been improvements (and I love things like Ergo shifters on my roadie and crosser and the disc brakes on my MTB), the only things that you need on a bike are the same things that you needed when you last rode. These other things you'll get told are "essential" are nice, but just remember - the old rule about the biggest improvement that you can make to your bike is a good set of wheels still holds true, so I'd suggest that if you are comparing bikes on componentry, place most of the comparison on wheels. But again, as RDV4ROUBAIX implied - the most important thing is that you feel comfortable, safe and enjoy the ride.
Have fun - and if any of this proves any help, let us know what you end up with ...
Oh, and just remember - the best frames are alloy (and made by Cannondale), Campag makes the best groupsets and handbuilt wheels are the way to go ....