Welcome Jason.
Your question is a reasonable one, except that for air gunners, you might as well be asking "what is the meaning of life?" There seem to be dozens of "right answers" that depend entirely on the shooter, skill and personal preferences, how much $ is available, how much weight one is willing to lug around, and philosophy of "shoot it out of the box" vs. "tune/modify it immediately", and what you intend to shoot (paper, varmints) and kill (time, money, varmints).
Don't look to pure velocity as the best indicator. Manufacture's advertised velocities are almost always overstated and even when accurate, are with pellets so light that, with springers in particular, it is probably harmful to the air rifle to shoot them. -- almost like dry firing a springer. The better indicator is foot-pounds of energy (FPE) rather than velocity in feet per second (FPS). But even then, there are always more factors to consider, probably most importantly, what type of power plant do you want -- springer, CO2, compressed air (CA)?
In general, remember that most will want to scope the rifle, which adds additional cost after the purchase. I have found that it is usually better to buy a gun un-scoped, and then choose a decent quality scope and mounts separately. Many (not all) of the "package deals" sell you a low-end scope that won't hold up for very long, particularly with a springer and may be less quality optics than you really want.
I have begun to think about my air rifles in two categories that I find most useful: 1. Accuracy, and 2. FPE per dollar spent. To seriously assess these, you have to be able to shoot the rifle, because, as they say, individual results may vary, and you have to have a chronometer to measure the velocity and calculate the pellet energy. But it is not always the fastest or most energetic pellet that shoots best in a given air gun. If you plan to shoot targets, perhaps competitively at 10 meters and want maximum accuracy (God help you), then expect to spend more (perhaps LOTS more) than for a decent plinker/hunter.
My opinion (and it is only an opinion, and I do not claim an expert opinion) is that long term satisfaction usually mandates a tune. So . . . here goes:
Best "starter" target rifle for the money -- Daisy 853 Avanti 177 single pump pneumatic target rifle.
Best "starter" springer air rifle for the money - Mike Melick tuned B26. You can get a tuned 800+ FPS, 13 FPE .177 cal or 600+ FPS, 13 FPE .22 cal springer from Mike for under $200 shipped with a nice trigger and shooting very good groups out of the box. With a decent scope and mounts, that "package" can be had for under $250 and you will be hard pressed to find a better deal. Consider an RWS Panther 34 also, but the later will benefit from a good tune and take you higher in price range if you go this route.
Best "starter" CO2 air rifle for the money - Mike Melick tuned QB78. Consider the Hammerli 850 if you might want a bolt action repeater. Remember, CO2 guns cost more to shoot after the initial investment and in cold weather (less than 55 degrees or so) performance suffers.
Best "starter" CA air rifle - I hear good things about the Benjamin multipumpers, particularly tuned. Consider also a pre-charged pneumatic (PCP), like the Discovery. But either way, you will have to pump the action, or pump the hand pump, or buy stored compressed air in the form of a scuba tank and fill apparatus, which again, adds expense. I don't have or shoot any CA weapons, other than my single pumpers, but there are lots of "Dark Siders" who will sweetly lure you, like the Sirens, to the promise of superb accuracy and almost unlimited power.
Enjoy your Oddesy!