Sore = Better Workout?

Id love to hear the answer to this too. I've heard that if you're sore, you've worked your muscles well, and that's how they get stronger, but I don't know. I eat a lot of protein, drink tons of water, and stretch really well, and im rarely sore, unless I really push it. Im getting stronger too. Ill be stalking to see what others say.

You are sore from lactic acid in your muscles. That is a good sign that you worked them well. It will ease up as your muscles get used to it. It is good to be sore (in a good way of course, if it is your joints then you need to back off). If you are working with weights and are not sore the next day or 2 then you are not hitting them hard enough. Muscles also need time to repair themselves (5 to 7 days on average). It is best not to work the same muscle group consecutively but instead change it up. Generally my routine has been...
Day 1: Shoulders
Day 2: Chest/Back
Day 3: Legs/Abs
Day 4: Rest
Day 5: Arms/Abs (although you should try to do some abs with every work out, they are the exception to the rule).
Day 6: Free Day (whatever I feel like, being a guy it is usually chest and maybe shoulders and/or arms again if they can handle it).
Day 7: Rest...start over on Day 1.

At least 3 sets of each excercise, utilzing several excercises. try to make your work out an hour long.
10 to 12 reps per set (for men) at a weight that brings you to muscle failure.
Higher reps, lighter weights for women, more like 15 to 20 reps.
Most imprortantly...LEAVE YOUR EGO BEHIND.
Use weights you are comfortable with using good form.
Overloading and doing sloppy reps will give you less results and will most likely cause injury so be careful and use a weight that you can control through full range of motion.
Also, take advantage of negative reps for faster results.
Meaning don't just drop the weight, instead control lowering (or the opposite of what you are doing) the weight slowly.
One more thing, machines are great for isolation excercises but free weights/body weight excercises incorporate the supporting muscles and will give a better overall work out. Isolation is good to work a specific muscle, just don't neglect the supporting cast along the way!

Generally I feel pretty sore the next day, but a good soreness.
If you feel down right bad, ease up and take it slower.
It is a marathon, not a sprint!

By the way, I just blasted my legs with Squats 2 days ago and they are still pretty sore!

Lactic acid build up causes the burning sensation during excersize. That fades with time.

Soreness isn't necessary the best indicator of a good workout. It could also mean you had poor form on your lifts, insufficient nutrient intake, or a bajillion other things.

The best sign of a good workout is strength/endurance gains. This takes a few weeks to show. Stick with it, I'm sure you'll see progress.

Yes and no...
When you are working your muscles you are damaging the muscle fibers which will repair themselves over time growing larger/thicker. The soreness is a result of the damage done and the repair in progress. If you are not feeling anything then you are not doing the damage required to cause them to grow in order to take on the next challenge. Lactic acid will ease over time, that is true as your muscles get more toned but soreness is a good indicator that damage was done.
You are correct about strength and endurance, that of course is the best indication.
if you are not raising the amount of weight as you go you are not gaining strength, meaning you are not doing enough damage to make those muscles grow.

As previously stated, if you are feeling soreness in your joints or tendons, you are not using proper form and will end up injuring yourself...proper form is key to a good work out!
This will end up throwing you off for weeks or even months, so not worth it.
I speak from personal experience.
I was really into my work outs over the summer and got too cocky.
Bench pressed far more than I would normally do, 350 pounds just to see if I could do it.
I did, 2 reps and threw out my shoulder so bad i was unable to lift until just recently.
There are different variations of soreness...
If you are feeling pumped up and kinda sore when you flex those muscles...good.
Just plain hurts/aches really bad...NOT good.
Nothing at all...up the weight/intensity of your work out as you are not doing the damage required to grow those muscles.