I'm a long-term low carber. Initially it was for weight loss, but the more I read about it, the more I'm convinced that this is a much healthier way to eat.
I never eat bread, rice, potatoes or pasta. I rarely eat any sugar, and only very occasionally eat any fruit - and then, only lower carb fruits, like berries or rhubarb.
I'm not especially convinced by the Paleo argument, as I can't believe the human race hasn't evolved sufficiently yet, but I do recognise that wheat/grains can cause massive digestive problems for a lot of people - so perhaps there is something in it.
I know that when I increase my carbs, and start to eat stuff like bread/pasta too often, that my IBS is more likely to flare up.
Once you've got out of the habit of eating things like this, it's not often that you miss them - although it has to be said that the world does revolve around them. If I'm out and about with work, eating on the go can be very difficult - everything is carb-based - sandwiches, crisps, chocolate, etc. So it does mean a bit more planning ahead on those days.
I also work from home, so it's easier for me to sort my own lunch out, which means I can easily avoid carbs.
In terms of alternatives - to be honest, I often avoid those meals where the carb element would have been the main feature. I cook the same meal for us all (although the rest of the family still eat carbs). If I do cook something like a risotto, I will have something different - but this happens only rarely and/or if a specific meal has been requested by the family.
If I make spaghetti, I usually just have the bolognese sauce with cheese on it, with some extra veg. Occasionally I have it on a bed of thinly sliced, boiled cabbage, which can make a spaghetti substitute. If I'm having chilli, I just have it with yoghurt and cheese on top, and no rice.
You can buy low carb tortillas and breaf from the Low Carb Megastore but they are expensive, and it's not as convenient as buying from Sainsbury's!
There are also some Japanese noodles, called shirataki, here which are zero carbs, which are fantastic for stir fries/Oriental dishes - and I have occasionally used them as a spaghetti substitute.
For packed lunches, things like:
hard boiled eggs, cooked chicken drumsticks/skewers, cold sausages (low carb ones!) are all great, along with pots of things like tuna mayo, egg mayo - great rolled inside lettuce leaves. Olives are good. Smoked salmon or slices of ham rolled around a stuffing of cream cheese; celery sticks filled with pate or peanut butter or cream cheese. Slices of cucumber, celery, peppers.
It's actually easy to avoid bread/pasta once you get your head around it.
And I'd also like to point out that doing this isn't about 'no carbs', it's about lower carbs. I get plenty of carbs, but they come from vegetables and salad.
Given that processed, easily digestible carbs are implicated in weight gain, obesity, diabetes, hypertension, heart disease, cancer and Alzheimer's disease, I'm not planning on changing my diet any time soon.