In furnishing a house, you have two avenues you can take: 1.) Go to the nearest furniture store and buy the matching couch/loveseat/chair/coffee table/end table/lamps OR 2.) furnish it over time mixing bought, found, and inherited pieces.
If you haven't guessed--I'm kind of more for avenue #2. Homes that can successfully blend pieces in a variety of styles, colors, and textures seem (to me) more inviting and reflective of their owners. It is a process though. You'll often find yourself "making due" as you save for or try to hunt down just the right piece of furniture or accessory. Over the last 15 years, I've lived in 5 houses and 2 apartments--and my furnishings have moved and adapted with me. Have a look:
This was my house in the country circa 1996. It was the first one I lived in after getting my design degree. I painted all the surfaces (including the fireplace) a creamy white and (you can see it reflected in the mirror) one wall in an oversized checker pattern. I worked retail for 5 months to save up enough for the Ethan Allen couch--worth every cent! Having run out of money after the couch, I supplemented with two (then) $80 wicker chairs and and $40 wicker table from Pier 1. The dark wood table was inherited from my Grandma, and the olive suede ottoman we made out of plywood, upholstery tacks and imagination. Besides having a little too much gold accenting going on (and the gray-blue carpet!), I think this home would still look new and fresh today:
This was the closest thing to a rental home we ever had--living in my mom's house for 6 months while she captained her boat around Alaska. It was wonderful to have such an open, light-filled space! She let me move in all our furniture, and even paint my beloved square pattern (turned harlequin here) on the stair wall. But--we had to just make the white walls work. The couch, wicker chairs, and ottoman made the move. We kept her oversized leather chair and barstools. And you can see our dining room furniture--a table we built with my Grandpa's help, and 4 chairs I found on a close out for $50 a piece at the Big Lots. I liked that the chairs were a lighter stain than the table: 
Here was the house we built in the "big city" in 1999. This was just a few days after moving in and it for sure had that "hello! I'm new and bare!" feel to it. The first ottoman we built had broke and we were in the process of building another (I was waiting for the material on order to finish the top!) We got the Mission-style rocking chair from my sister-in-law who worked at a leather furniture store. The living room was for sure the smallest I'd worked with and it was confusing to figure out where to put everything since I had what equated to a traffic path running through the middle of it:
Three years later, I'd lived in the house long enough to figure out exactly what I wanted to do with it and how to make the best use of space--which meant adding a few new furniture pieces. It's the same couch, but after 7 years, it was looking a little worn. Semi-custom denim slipcovers from Todo Es extended the life for a little longer. The small cube ottomans (which served as additional, movable seating) came from Pottery Barn Bed and Bath. I ordered a crocodile-embossed leather chair using my designer discount from Norwalk (it was my "splurge" and I STILL loooove it). Taking out the plant shelves made the room appear larger AND cut down on awkward dusting. It took 27 hours of intricate painting, but I loved the stucco look I created on the walls. Wide plank laminate flooring, a small wicker chair (found for $25 at TJ Maxx--I used it for working at my computer), and black and white photos of trees I took myself finished the look: 
Here's the view from the opposite side (and forgive the Christmas decorations!). My smartest purchase was two black armoires--one held my TV and stereo, the other my computer--allowing me to do everything in my tiny living room! You can see the dining room furniture is there too. The chairs got Pottery Barn slipcovers, and two galvanized chairs added to the mix. I described this style as "Italian Farmhouse".

Finally my house today. This is the most colorful space I've created for sure! My mom made me promise to buy a new couch with the money she left me when she died (that was my mom for you!), so a small scale, down-filled one from Room and Board replaced my old Ethan Allen. My once black computer armoire got a coat of bright olive paint (the other went into my bedroom). I converted an old coffee table my sister gave me into an oversized ottoman, covered in $5 a yard nubby charcoal fabric found in a remnant bin. I swapped painting for sewing with a friend and got the window treatments and slipcovers for the cube ottomans made. My crocodile chair got a pillow and throw. And finally, I found a scratch and dent model dining room table, painted chairs bought from an unfinished furniture outlet, and ordered the Karim Rashid Oh! end chairs for a mid-century modern feel. Other furniture (the leather rocker and Grandma's end table) now reside in my family room, and one of the first house Pier 1 wicker chairs is now the reading chair in my little boys' room.
WOW! That was wordy, wasn't it?! Still--just to prove that if you buy quality furniture when you can, and use your imagination to fill in the gaps--
you can create all kinds of looks with the same stuff! Now--isn't that better than buying the matchy-matchy group that will probably need replacing in 5 years?
(The answer is yes :)! ) Coming tomorrow and Monday: A few more before and after photos from my city house, and answers to the design dilemmas you gave me!