Looking at your profile, I assume you're not far from Manchester. If so...... walk down Deansgate and try on all the boots that Ellis Brigham, Cotswolds, Nevis Sport, Blacks and North Face have to offer. (Be sure to take the two pairs of socks that you're planning to wear with them). A good fit will influence you far more than folks' opinions on here.
I recently bought my first pair of B2s, but did try a few B3's on too:
The Nepals and the Scapra Mont Blancs seem to be the one most folk go for, but as they're both both quite heavy. If you're sticking to Scottish stuff, it's might be worth you trying on some lightweight B3 boots too.
In reply to mattjohnson1: You want the lightest ones that fit well - as said before try as many as possible. When buying check that you can return them if you try them around your house for a (good) few hours. It is worth looking at crampons too at this point, although not essential to buy at the same time.
In reply to mattjohnson1:
Personally I prefer durability to weight so i would consider leather boots. However unfortunately these tend to give me heel blisters so I now buy fabric ones - currently freneys.
I'd personally have a preference for b3 over b2, it gives you a wider choice of crampons that can fit as well as added support climbing. But to be honest fit is king if you are finding a pair of B2 is the most comfortable on get those.
In reply to mattjohnson1: I have just bought my first pair of winter boots and after trying on as many as i could found the Salewa Pro Guides in Outside, Hathersage. Leather, b3 adjustable to approx b2 and 'guarenteed blister free'. After a week walking in the lakes (no snow unfortunatly) no blisters!!.If you can get down there give them a try, i found them much comfier than anything else i had tried.
It may be worth bearing in mind that winter/alpine boots should last for years (depending on how much they are used, of course). So before making your purchase it's worth anticipating how much and what kind of climbing you expect to do.
La Sportiva Nepal Extremes are excellent all round boots and may be warmer in Scottish winter than some lighter boots. They are also good for alpine summer and can easily be resoled.
Might be worth buying a pair of cheap secondhand boots in roughly your size - something like the Salomon Super Mountain 9's that keep coming up - they'll last you until you have a solid enough idea of what you want to do in winter so that you can make an educated boot choice that will last you many years.
I.e. you buy nepals but decide you want to do hard mixed, or you want to do high alpine, or you have really bad circulation or whatever.
In reply to mattjohnson1:
As others have said, fit is the most important thing. I wear Scarpas - have used Mantas, Mont Blancs and Phantom Guides - but can't get on with Sportivas at all. Shame because they are great boots too! If you have the opportunity to try different types on then take it, it will be worthwhile.
B2 if you are planning on walking/ easy routes and want a bit more roll/ flex to the sole. B3 if you want to get onto harder routes. The bigger your feet are the more difference this will make. Lightweight is good, but they will last a bit less time so depends on your budgets/ how much you are going to be able to use them.
Again as others have said, worth considering crampon choice at this stage too and looking at the fit of what you want on the boots you get. Some boots with a very asymmetric sole or a narrow toe don't fit some crampons very well. If you can take your boots when you go to buy crampons/ take your crampons if you have some already to buy boots.