Do bigger telescopes equal better results? There are many large reflecting/optical telescopes around the world, just to name a few: the Very Large Telescope, Large Zenith Telescope, and European Extremely Large Telescope.

My question is does actually building larger telescopes improve visibility of the universe, quality of an image, and various other attributes of a telescope? 

Well it does seem kind of obvious that a larger telescope may have more magnification and better imaging, however if that is true than why don't we just build a super large one (think really really big, unlike the size of the current large ones) so we can see the universe in HD - so to speak?

Since we haven't done this yet (I think) is it because of financial issues or is it because simply building a bigger telescope won't improve much to visibility and image quality?
Magnification is not the main purpose of a telescope. A very small telescope will have a lower resolution than a larger one, but for larger ones, the atmosphere limits the amount of detail visible.

Large telescopes capture more light than small telescopes. More light means that dimmer objects are visible, and there is more light to be analysed. A very dim object, such as a planet orbiting another star, needs a very large mirror to collect enough light to analyse spectroscopically. And this is the reason why larger telescopes are made. Of course larger telescopes cost a lot, and cost is the reason that telescopes like the "Overwhelmingly large telescope" was not built.

Much of the development in telescopes in the last 25 years has been not in ever larger mirrors, but in adaptive optics, or using two telescopes together as an interferometric telescope.