You seem to be asking two questions...
1. Computer speakers:
If you're looking for really good sound from a computer, the weak link is typically the internal soundcard (even the "high-end" feature-laden soundblasters). You'd have to spend at least a few hundred dollars to get a decent external USB DAC, and get the conversion out of the noisy computer box. But if you're like me, and just use computer speakers for watching plot-driven movies in 2-channel, and for pre-listening to mp3's before buying the actual CD, you should just go to a used computer store and buy several pair of older computer speakers. People always get rid of the older ones that were way better-made (and often better-sounding) because their new computer came with the cooler-looking black and silver speakers. I have a shelf full of heavy-ass white computer speakers that cost $5-10/pair, and sound fuller, tighter, and less boomy than most of what's at Best Buy today. Finally, if you really want new computer speakers, I suggest Klipsch Promedia Ultra 2.0, which is about the only new consumer-oriented computer speaker I've found that sounds acceptable for music.
2. Loudspeakers
If you think that last paragraph was long, most of us could write infinitely about loudspeakers-in-general. What amp and source components are you using? In what sort of environment are you listening? Etc., etc... I'm guessing that you have a fairly typical Japanese solid-state receiver? I suggest looking here on Audiogon for some used NHT, B&W, or Paradigm in your price range. Any of these would please you now, and grow with you later as you upgrade other components.
1. Computer speakers:
If you're looking for really good sound from a computer, the weak link is typically the internal soundcard (even the "high-end" feature-laden soundblasters). You'd have to spend at least a few hundred dollars to get a decent external USB DAC, and get the conversion out of the noisy computer box. But if you're like me, and just use computer speakers for watching plot-driven movies in 2-channel, and for pre-listening to mp3's before buying the actual CD, you should just go to a used computer store and buy several pair of older computer speakers. People always get rid of the older ones that were way better-made (and often better-sounding) because their new computer came with the cooler-looking black and silver speakers. I have a shelf full of heavy-ass white computer speakers that cost $5-10/pair, and sound fuller, tighter, and less boomy than most of what's at Best Buy today. Finally, if you really want new computer speakers, I suggest Klipsch Promedia Ultra 2.0, which is about the only new consumer-oriented computer speaker I've found that sounds acceptable for music.
2. Loudspeakers
If you think that last paragraph was long, most of us could write infinitely about loudspeakers-in-general. What amp and source components are you using? In what sort of environment are you listening? Etc., etc... I'm guessing that you have a fairly typical Japanese solid-state receiver? I suggest looking here on Audiogon for some used NHT, B&W, or Paradigm in your price range. Any of these would please you now, and grow with you later as you upgrade other components.