I upgraded my bike some recently. It was been working out very well. I had seen the new FSA Metroplis handlebars and I thought they would be nice. The problem was price. First they are ~$50 and second they would not fit my current quill stem. So I would have needed a convertor and a new stem. That would bring the total to at least $80. Instead I found some similar shaped bars that did fit my current stem.
My old shifters were grip shifters which turn out to be too convenient. I found myself sometimes shifting or half shifting without meaning to. So I was interested in replacing them too. I at least needed cables and housing, since I was using 15 year old stuff. I think that just cables and housing would have been $15 to $20. I was offered a set of combined Shimano shifter and break levers complete with cables and housing for $30. So I decided that was worth it.
I added some $10 ergonomic grips with palm rests.
I got it all put together and adjusted pretty well. Now having ridden it 5 or 6 days, I can say it was a good upgrade. The handle bars are set to be higher and more swept back than the originals. I feel more comfortable. I can still stand and climb and I have not noticed my average speed suffering at all. The hand position is definitely better.
I also recently replaced the chain and cassette. I am practically riding a brand new bike for just over $100. Really makes it hard to justify the $8600 Black Sheep bike I dream about.