You are right about laptops being difficult to repair, but if you look after your laptop is should last.
Benefits of laptop,
Portable
Battery power, helps when there is a power cut
Takes less desk space
Performance, good as a PC
Disadvantages
Gaming - unless you buy a gaming laptop, very expensive
Heat, some laptops have poor cooling.
Repairing, difficult / part availability (higher repair costs)
I own a Samsung R510, which i have found to be a great laptop. I paid £375, 6 months ago.
Benefits of a PC
Easy to repair (and cheaper)
Overall more powerful
Cost less
Disadvantages
Not portable
Takes more desk space
Uses more power (electricity)
If buying a laptop, avoid Dell and HP, they run at 19.5v and 18.5v respectively. it is harder to find universal power supplies at these voltages.
At the end of the day, its your choice.
I would suggest making a list of all the PC's and Laptops you are interested in, then comparing features / specification / performance and price.
Work out which is better for you or which is better value for money.