I'm no audiophile but I do appreciate high quality sound. I can't count how many different amps, speakers, and headphones I've purchased over the past 20 years. It seems like I'm always searching for something just a little bit better. Finally though, after years of searching, I feel like I've found the best audio setup for the money.
When searching for speakers for your office you might be tempted to simply search for "computer speakers." This will bring up thousands of small, self-powered speakers. Some of them may even come with a subwoofer. Perhaps the most impressive "computer speakers" I've heard are the Bose Companion 5 Multimedia Speakers. For their size, the sound they produce at medium volume is pretty incredible. The problem is that they are $400 and they tend to change the sound in certain cases to keep from distorting at higher volumes. 99% of users would never have an issue with these speakers but for $400, we could build something much nicer.
I personally own many different brands of speakers but I continue to find that my favorite (affordable) audio brand is Polk. I've found that for the money, nothing beats them, at least nothing that I have tried so far. Because of that I've built 3 audio setups that revolve around Polk speakers. Each setup will allow you to upgrade components later as your budget expands or you become more interested in audio.
Less Than $100
This is a great place to start with a lot of room to upgrade. You're starting with decent quality bookshelf speakers and an extremely cheap amplifier to push them. You could easily add a subwoofer to this system or upgrade your amp when you get more cash without any guilt.
If you can't afford a subwoofer right now, this is setup I would suggest. You're buying high quality Polk speakers that you will probably keep for the rest of your life and you have a solid Sony amp that is powerful enough to push much larger speakers if you upgrade one day. If you ever decide to buy a subwoofer, this setup won't require any other upgrades.
This is the exact setup that we have purchased for five of our work stations. I have not heard any system that can compete with this one anywhere around this price point. The speakers are small enough to fit on any desk but they aren't so small that they lack the mid-tones that so many other "computer speakers" fail to produce. The 10inch sub is shockingly powerful when it needs to be but at low volumes doesn't rattle any walls, it just adds depth to the sound. The Sony amp has plenty of inputs and power and has the ability to push audio to both "A" and "B" speakers. The only downside is that the Sony receiver is quite big and does require a large desk to place it on or to hide underneath. If the amp is too big for your needs check out the FX Audio D802 2x80W or the Topping TP22 TK2050
There is no doubt that you could spend more money and get higher quality sound but I believe that after this price point speakers, amps, and subs get exponentially more expensive without getting exponentially better. This $350 system seems to be the ultimate "bang for your buck."
Of course I am not claiming to have tried every amp and speaker ever made. I am simply sharing the knowledge that I have gained from years of searching for high quality, yet affordable audio gear. Hopefully this will at the very least steer you away from those "all in one" sound systems. If you buy each piece separately and you'll have much more control, higher quality sound, and hopefully, if you can control yourself, you'll save money as well.