Your mileage will vary with different translations. How do you wish to experience the poem? Are you looking for a literal translation? These are usually rougher sounding to our modern ears. Do you want a version that maintains the structure of Anglo-Saxon poetics, with alliterative verse and marked caesura? Or perhaps a prose translation that's a bit easier to digest?

I'll address the last example first. Seamus Heaney's translation has been a gold standard for sometime as an introduction to Beowulf. He does take license with the text. For example, the first word "Hwæt," an Old English interjection traditionally translated as "Listen!" or "Harken," he translates "So." I do enjoy this version for maintaining the Anglo-Saxon kennings such as "God-cursed Grendel" and "wine-hall" to name a couple. Heaney's native Irish turns of phrase appear often, so while not the most faithful translation, it does have an immediate familiarity for the first time reader.

For an accurate translation, many scholars use Howell Chickering's translation from 1977 for teaching the poem. It has a facing translation if that becomes something you decide you want. Be forewarned, this version is a terse read and will not be as pleasurable as Heaney's in terms of readability. I do enjoy its (somewhat limited) imitation of Anglo-Saxon poetics.

An exhaustive, annotated list made by a preeminent Beowulf scholar, Marijane Osborn is available here

The Tolkien translation is great if you want a Tolkien flavor, but was not intended to be true to the flavor of the original poem. There are lots of 'knights' in the tale, for example!

The standard edition for scholarly work is Klaeber. If you were to cite the poem in a scholarly paper, or to do a linguistic analysis of the text, this is what you should use.

If you're just looking to read nd enjoy it, Heaney is well regarded (as /u/deconnexion recommenfs). I personally don't like Heaney--but that's for some very specific reasons (he translates almost every mention of the word 'spear' into something else, why?!). Heaney is probably your best bet.

But I personally really like Michael Swanton's translation. Yes readable, and very faithful to the original. It's a good balance between the more poetic Heaney and the extremely scholarly Klaeber. If you have academic as well as literary interest, but don't want a full critical apparatus, that would be my recommendation.