Considering Buying A New Laptop

I am trying to work on troubleshooting my 5 year old laptop, but eventually I will need to purchase a new one.

I dislike the idea of this for many reasons, chief among them is I do not know much about PCs and I do not feel comfortable buying something I don't much about.

Last year I bought a TV, it took a year of research, but I knew the specs and what I needed.
I knew the important thing was:
1) Brand 2) Resolution (1080p) 3) HZ rate

With computers....I do not know which brand to get, what specs are important, nor what specs I need for my purposes.
Can any of you help?

I use my computer mainly to
1) Surf the web
2) Compose documents in MS Office and Excel/Powerpoint
3) Download and play music

In addition in the future I may need to use it do GIS work.
I have a dell, and don't like it too much.
I'm not sure though there is a better brand. Have heard good things about Mac...but it's too costly and I don't want to learn a new OS...and I heard it is bad for GIS too.
On the other hand I don't want the bugs I have to date.


My questions
1) What laptop brands are the best and make most sense
2) How much is this going to cost...not looking to break the bank
3) What are the important specs AND what do I need in each spec
(example...TV an important spec is picture resolution which was said to be 1080p)

Thanks!