Lol.
Sorry you were destroyed for asking that question, for all the flaming that happened, people could have just said "Google it" and left it at that, or just ignored the question entirely. Or as some have been in recent posts, provide insightful comments. At the same time, asking about MP3 bitrate is about as exciting red meat troll bait as asking "what OS should I use," or "what laptop should I buy?" (please don't ask those questions

)
My personal preference is to play nothing lower than 320, and sometimes I'll buy the .WAV of tracks I know are killer, and wan't to absolutely have maximum impact. People often state that "HD Space is so cheap! buy .WAV!" but there is also the extra $$$ associated with buying higher quality music. And maybe you don't want to use an external HD for holding your music. And maybe you have a massive sample library installed on your laptop, because you use it for production too... etc etc.
In short, you were flamed because everyone's situation is very different. Depending on what you are doing with your DJing career, the additional cost, and other factors might influence your choice. If you are happy with what you are doing, great. Realize that there will always be room for improvement in every aspect of your rig. No one starts out megaboss. Some are easier to affect than others, but you've gotta start somewhere right?
If you are playing for house parties, or some small/medium venues, 320 should always at least get you by, but what these guys are saying about a "statement of your quality" definitely holds true.
Another thing that is almost as important as high quality files, is to find an external soundcard if you don't already have one. A decent super super cheap option is the NI Audio 2.
Also, quick note:
Some tracks are encoded as Variable BitRate. 192 VBR sounds quite better than 192 constant BR. What ShadX said about the encoder used also makes a big splash. The biggest hint truly is "If it sounds like junk, trash it immediately."