Probably best to not go through the specific components on my bike, however, the sprockets, chainset, jockey wheels and chain need replacing due to excessive wear. Coupled with that, the cables are in need of replacement too. The rear rim is wearing a bit thin so a new wheel might also be prudent. 

I have done some back of the envelope calculations and the parts bill alone comes to 2/3 the price I paid for the bike originally. Hence, do I just get a new bike? If I do, can I just throw the old one away without any qualms about wasting what is a nice bike, albeit worn out?