Actually the lounge is the only place that users of hosts hang out. Ironically it's probably the only place on WHT where a user will get true feedback. Now he can expect a long page where 10 hosts will respond and there won't be many recommendations.
(Yep, not lost my cynicism)
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Any particular reason for mainstream in this case? I only ask because you want 50 GB for under $20, which is doable, but not by many mainstream providers, which, as you acknowledged, are usually more expensive. If you want the likes of Verio, Pair, Hostway, etc. you'll have to think about increasing your budget (in most cases, doubling it).
However, there are still some quality exceptions out there, such as MediaTemple, who offer 75 GB transfer and 20 MySQL for $19.95. They're extremely reputable. So a Search on them here and see.
Other than (mt), I'm not really sure of much else you'll find in the "mainstream" category who fit your needs for under $20.
Well, they just got the number 1 uptime mark again from Netcraft (link), which is quite impressive, considering all the other great hosts they compete with. I don't think you'll regret going with Hostway. Good luck, and give us a review later on!