So for all the charges that suits (and clothing consciousness in general) represent superficiality and worldliness, why do our clergy have standardized, formal, arguably showy and impractical vestments? Does this hinder them from doing the work of the people?
My point is that the Church clearly doesn't share the view that clothing (and how we appear before God during His services) is unimportant and "worldly." Not only is it a tradition from the Temple days, but it's part of our complete worship, including sights, sounds, smells, etc.
I'm not saying that a suit is the same as vestments, but I think the whole "I'll wear whatever I want, so long as its comfortable" argument works better for the Evango crowd with their bluejean wearing ministers and anti-sacramental services. There is a certain intrinsic formality to the Church and its services, and I think that wearing something fairly decent is compatible with that.
As others have stated though, modesty (true modesty is one thing. Stubbornness, laziness, and apathy is quite another) is the most important thing. So while a flashy, expensive suit/dress, shoes/heels are inappropriate, so are shorts, t-shirts (short sleeved shirts in general). That's certainly part of how monasteries and many parishes here and in the "old countries" interpret modesty.