I've only just seen this Steve, not yet had a chance to read through all of what's been said as there seems to be an awful lot.
However, here are my thoughts on the topic:
Definitely go for a laptop that has an SSD (solid state drive) fitted - SSD's are more expensive in comparison to their equivalent mechanical HDD, however, the faster load times will make it worthwhile spending the extra cash. You can also choose to go for an SSHD, which is a hybrid of both an SSD and a HDD, it compromises a bit on performance as it isn't as quick as an SSD, however, it's faster than a normal hard drive and offers you more space for less money (which is an SSD cannot do).
Processors - if you want the laptop to be future proof, personally I would go for a mid range i5, whilst you might not be harvesting all that processor power right now, as the laptop ages and technology develops you still want the laptop to be able to cope with newer applications.
RAM shouldn't matter too much, but definitely get a laptop with at least 6GB (which most these days will have anyway).
In terms of brand, I've had 3 HP laptops, 3 Toshiba's and currently on a Dell. What I found interesting is that 2 of my Toshiba laptops had a Samsung hard drive in them and one of the HP laptop had a Toshiba hard drive in it.
Point is that despite what it says on the casing, it is more than likely that not all components are made by that one manufacturer.
Toshiba would win in reliability (this is only from my experience). All 3 of the HP laptops had issues with overheating and ultimately caused the motherboard to fail a couple of years after purchase. I don't know what HP are like at the moment as I've not used their laptops for three years now but they did have a reputation of overheating a few years ago.
Having said all of that one of my Toshiba laptops did catch on fire
It may be a bit more expensive buying in store than it would be online, however, the after sales support that you get if something were to go wrong is loads better if you were to buy it from a store rather than online -- you can walk in with the laptop and they'll deal with sending it off to the manufacturer etc. Yes, you might save a few quid buying online but should something
Hope that this helps, I'm sure most of this has been said already in previous posts.