As for using a TV, check with the TV you are considering first. Most these days, even budget TVs, accept inputs from multiple sources (antenna, cable, DVR/TIVO, Game Consoles, and Computer). Ideally, you want to use digital all the way so your desktop should support DVI or HDMI, and so should your TV. Note that the video signal with DVI and HDMI is exactly the same so if one device does not support one of the connections, adapters are available. The main difference is HDMI also carries 5.1 surround sound in the same cable. BUT - some computers that support HDMI don't route audio through HDMI, so you may still have to use separate audio cables to get sound to the TV's speakers, if that is what you want.
Overclocking is very iffy, and way-too-easy a thing. Most new motherboards allow some overclocking with simple software or BIOS settings. BUT (that's a big but, if not obvious) damage from overclocking is NOT covered under any warranty! If something goes wrong and your CPU or graphics card go up in smoke, it's out of your pocket. If an overheated CPU fails to shutdown properly, and destroys the motherboard socket, then even the motherboard makers will cover the motherboard under warranty. Therefore, I don't recommend it unless, and until, you have fully done your homework, fully understand what overclocking really means in terms of voltages, current, and heat to the motherboard, CPU, RAM, graphics card, power supply, and case cooling, AND you are still prepared to accept and suffer the consequences (to hardware and your files) should something go wrong.
Understand that years ago, overclocking was purely for the ubergeek and required soldering jumper wires on the motherboard, and a steady hand. Today, it is pretty much a marketing gimmick. Engineers don't design CPUs to be overclocked. They design them to be stable at designed speeds, or in the case of cutting edge, as fast as today's manufacturing technologies will permit and still remain stable.
But when marketing weenies gets their hands on it, they dummy down the specs so users can move them up again and feel good. The problem is, all is fine until there's a problem and then the motherboard makers (and it is on the motherboard where CPUs are overclocked) disavow any wrong doing if the CPU fries, and CPU warranties CLEARLY state damage from misuse or "abnormal conditions" are NOT covered.
If are not a serious gamer, you don't need it. If you want to do it anyway, don't do it on a production machine (one needed for work, school, or important household work). That would be like taking the one and only family car to the race track.
IMO, if you think you need more power, budget for it, and buy it.