Ok, so I was levelling a mage. At first, they started not allowing me on the fast travel trains, I could live with that. Now that my Magic rating is 85, the shopkeepers wouldn't even talk to me. And I can't repair my armour and weapons. So is there a need to maintain a balance or should I get the Repair skill. Don't feel like wasting points on Repair.

you can use a save-game editor for repair. when I play, i do this for all my characters, since it's a pain having to deal with their stuff anyway. I haven't played as a magick character, but are you sure the magick armorers don't repair magick gear? like the ones in tarant?

When you say they "won't talk to you," what do you mean? What actually happens when you try to talk to them?
If you really can't do business with the Tarantian merchants anymore, don't worry. There should still be plenty of merchants in other places to trade with.
1. The elvish merchant in Ashbury.
2. Anyone in Caladon.
3. Anyone in Qintarra.
4. Anybody else who sells magical goods, like those gypsies who can identify items. There's one outside Tarant, isn't there?

You only can't barter with overly technological shopkeepers. There are still three shop keepers in Tarant (besides the wise woman, the fence, the general store, and the clothing store) who will barter with you.
Also, like Prator said there are lots of other places you can go for different merchants. Though to point out: Caladon does have some tech merchants who won't trade with you. But that is a minor detail.
So, have no fear there are plenty of people to trade with, you are not actually being handicapped.
As for repair, don't level it-it is a waste (unless you're RP a character who has repair), also it is a tech skill and so will lower your magic rating. In Tarant at least one of the magical merchant shops is a magical armory and will repair your gear. I also believe the smith in Shrouded Hills will repair your things. Again, you just have to find the right people.

Yeah, the shopkeeps will just say that I'm a powerful mage or something and refuse to trade or repair my stuff. And their attitude rating towards me drops everytime I speak to them.
So far I've not met any of the Magic Shopkeeps who can repair my armour yet. I've got a Glove of Dex + 2 breaking on me and I can't use it anymore, red and broken, beyond repair, sad..
I'll try the rest of the merchants, thanks for the hints.

If a tech shopkeeper's reaction to you drops to zero (or a mage one for tech characters) because, say, you insulted him/her enough, then they will attack you. Killing them in self-defence allows you to then rob the shop blind. ;-)
It's not even an evil act, though I tend to RP my good chars and not take advantage. My evil characters however ....

Same for me, only on the opposite side of the spectrum. However, it's only annoying 'cause this way I have to resort to general stores to buy HP/Fatigue restorers for Virgil, and they mostly only carry the lesser ones. Oh, and because I just can't seem to find a decent, non-magical armour with a high FR rating.
As others pointed out, there are magical smiths around; I clearly recall there's one in Caladon (if you're that far in the story, that is, but, given you're so high on the magic scale, I suppose you are), and I think there's one in Tarant as well. Also, there's an Elven junk dealer in Ashbury, near the docks; I think he repairs stuff.

So far the magical merchants in Tarant don't repair stuff. Neither does the Smith in Shrouded Hills, he talks to me though. The Gypsies who identify items don't either. And tried the Elven junk dealer, he resold the 2-Dex Glove I broke earlier, but he doesn't repair stuff too. I'll try the ones in Caladon once I get there.
Now I try not to get into fights physically so as to prevent armour damage. I summon the Fire Elemental, he seems to punch through most mobs in 2-3 hits lol.

I find one of the most useful merchants is the junk dealer on the docks in Tarant. He's right near where you enter the city so you can get there quickly, he'll buy pretty much anything you care to sell him, will repair items and has no tech/magic bias.

this!
I totally forgot that he can repair stuff. He is the guy you want to go to.

Very useful guy indeed and cheap when it comes to repairing stuff.
You do get a better price for items when you sell them to store keepers, so I tend to only sell things to him I can't sell to storekeepers in Tarant.

Sorry for keeping straying off-topic, but...
I tend to buy up his supply of small and large springs, railroad spikes, broken flintlock pistols, revolver parts and small tubes, combine them with each other and things purchased from other stores (metal casings and revolver chambers) to make spike traps, hand-crafted flintlocks, fine revolvers and trap springers, then sell these all to the general store clerk (my char is an expert in haggling). This gives a rather nice profit with only two points invested in two disciplines.

Ah, thanks! I'll go check it out!

Liam's mother in Black Root will also repair items, but I don't know if you get access to that part of the conversation tree every time you visit with her.