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Dan,
As the several respondents here have suggested, something like an 8 - 24 mm zoom eyepiece is a really handy all-purpose eyepiece in most telescopes, providing a reasonably wide-angle view for scanning, and moderate magnification for basic lunar observing, brighter nebulae, etc. (It's also really handy if you have a refractor or Mak with an erect-image diagonal, for use as a zoom terrestrial telescope.)
My 7.5 - 22.5 mm "lives" in my 130 mm Newtonian (650 mm focal length) as my "starter" eyepiece, but I tend to swap it out for one of my Plossl eyepieces with optimum focal length once I have found a target. In my 650 mm focal length telescope, it gives me a magnification range of 29x to 87x, and a Field of View of about 1.4 degrees at 29x (about three times the disc of the full Moon), down to about 1/2 degree at 87x (just big enough for the whole disc of the Moon). Longer focal length telescopes will have higher magnification and narrower field of view, and vice versa.
The Seben zooms (and I imagine many of the "clones" which are the same eyepieces under different brands - but I don't know how you would tell without trying it out) are exceptionally good value for money, especially for beginners. No, they are not as good as a premium zoom, but they are a fraction of the price, and provide a reasonable view. The view isn't as sharp or bright at any focal length as a reasonable Plossl or similar, but the convenience of being able to zoom in and out, with minimal refocussing, makes it a worthwhile trade-off for me.
Note that an 8 - 24 mm zoom pretty much spans the range of the standard two eyepieces that many basic telescope kits come with (10 mm and 25 mm or similar being a common pair of starter Plossls), so it doesn't really add anything to your viewing range, but it's the convenience of being able to view at any magnification in that range that is handy.
In all probability, you will still want to add at least one higher power eyepiece for planetary work (6 mm or so - or maybe a 2x Barlow with a 10 mm), and one lower power / wide-angle eyepiece (say 32 mm - 40 mm), but a basic zoom is a good buy as one of your first upgrades.
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