I always chip in on this whisky threads, I'm far from an expert but I have some opinions, in fact I've lots of opinions but you don't have time for all of them
The thing with whisky is you can spend a fortune so if we assume you are restricting yourself to something that you might just be able to justify as a once in a blue moon special present to yourself, say less than £100, then here are my thoughts:
Black Bush from Bushmills is hard to beat as a blend and general drinking whiskey and is about £20 a bottle. The 21 year old Bushmills single malt is supposed to be wonderful but I've never tried it.
As you say the Macallan is fantastic drinking and the standard malt is good but the 18 year old, which can be had for less than £100 sometimes, is worth a try if you can justify it. It is like the standard Macallan but more.
We couldn't not mention Glenfiddich on a stalking web site and I would recommend the 21 year old. You can get this in Glasgow/Edinburgh airport for just a shade over £50 a bottle and it is worth it for a treat. It is probably the best affordable whisky in the sense that I feel it punches a little above its weight. (just like Minox HG binos for example

)
Worth a try is the Tomintoul 16 year old, or even the 27. It is good whisky and you can get the one litre bottles of the 16 in Glasgow/Edinburgh airports for £30 which I think it really good VFM.
I have tried a lot of different malts and in my very ignorant opinion it is usually hard to beat the big name brands. I always feel I want to support the smaller operations, and each will have its own claim to be the smallest, or highest, or lowest, or something distillery, but in the end buy the Tomintoul 16, the Glenfiddich 21 and the Macallan 18 and I think you will not beat them.
You will notice the Islays missing as I like the odd glass but am not a big fan and for all I know this post might directly contradict the last one I made on the subject but I change my mind a lot!