Whenever the option is there to go with solid stock for legs, thats my choice hands down. Especially when working with figured woods or wood where the grain is a dominate feature. Keep in mind that everything is relative. What I look for and what you look for may or may not be the same. I like to see consistency around the leg. ie. how the grain flows or the color is consistant etc.. BUT that is something I look for, most folks who don't do woodworking may not even notice. Those that do, may or may not care one way or the other. Still others may be somewhere in the middle.
There are alot of resources out there that sell "leg" stock. This is another good way to save a few bucks. Only concern will be color matching. Even pre-fab legs.
Glueups are a great option. Especially when trying to keep costs down on a project. Here, wood selection is key. Color and grain pattern is important. If you can pair up a couple boards that 'blend' together well, your average Joe will never notice. And for the folks who look for such things, a good glue-up won't go unnoticed. A well thought out finish schedule can also hide the fact that multiple boards were used.
Your mention of 4, 45* is another option, but one you might not want to tackle just yet in your evolution as a woodworker. The longer the leg, the longer the odds of getting it perfect. Knowing your penchant for perfection, this may just send ya over the edge
The only time I would go with a veneer is if I knew for certain that the leg/s would not see any traffic. You could achieve a great look with veneers, but veneers can be prone to nicks and chips especially when subjected to high traffic or use.