I think you can actually get a decent pair for your price -- far better than 15 year old monarchs (which I have some similar experience with!). I'd also suggest going with an 8x42 vs 10x42. In that general price range of glass I notice the 8x are a bit more clear, have a wider field of view, and you can often see more detail than a 10x. I put a lot of effort into upgrading my glass a few years back when my hunting backpack (with binos) was stolen. I tried out just about everything I could get my hands on, and was blown away with how just about everything I looked through was far better than my old Monarch 10x42s. Optically I was actually most impressed with Bushnell for the $200-$300 range, but their warranty and customer service made me keep looking. I spent the extra money and got a pair of Monarch 7 8x42s that were truly great. Since then I upgraded again and got into some Meoptas... but they are quite a bit more.
I looked at Academy, Cabela's and Bass Pro. Academy doesn't have much of a selection, so I think I'd go to Cabela's or Bass Pro (which are essentially the same company) and get the Monarch 5 8x42, ($299.99 so tax might push you over $300). I honestly haven't tried the Vanguard Endeavor EDs, but it sounds like they are a good option that is also sold there ($299.99), and if those don't work for your price (...darn taxes!) then I'd just go with the Vortex Diamondbacks ($219.99). If you can look at them in person you might try out the Bushnell Legend L Series ($279.99) and see if you like them better than the Diamondbacks. And ultimately, if you are hard on your stuff then just forget everything I just said and go directly to Vortex and get a pair of Diamondback 8x42s because that warranty is pretty much unmatched.
