Plugging speakers directly into the headphone jack on your laptop generally works just fine, but it could work finer. The digital-to-analog converter on most laptops is adequate at best, but a relatively inexpensive doohickey like this HifiMan sound card could give you quite the boost in quality.
For $39, this wee box claims to give you an audiophile-level boost in sound quality. About the size of an iPod Nano, it won't take up too much room on your desk, either. It plugs into a USB port and features output jacks for both speakers and headphones. Are there bigger, more expensive options that'll do even more for you? Sure. But this one is $39, and by all accounts does a damn fine job. Seems like a good deal to me.