It's been my experience that most amp sims are okay to practice with, but can be quite "thin" sounding when it comes to recording. To get a sound closer to a real amp requires some creative layering, eqing, panning etc.
If you're just talking about practicing/playing along with pre-recorded music, then any decent studio monitors should do the job. Keep in mind that it not going to sound as good as what you perceived with your headphones, and it won't come close to what a real mic'd amp would sound like.
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