I would agree with Zach, and further find the Scriptures, especially the Psalms themselves, speaking to "sing a new song" unto the Lord (e.g. Psalm 33:1-3, Psalm 96:1, Psalm 98:1, Isaiah 42:10), and at liberty to make use of God's gifts of instrumentation to us, as we are "filled with the Spirit" and make melody unto Him (Ephesians 5:18-19). I understand that EP advocates argue these commands in the Old Testament are not applicable under the new covenant but I find this unconvincing. I see church history as agreeing with the singing of hymns and spiritual songs (not Psalms exclusively) in this way. Whilst I don't claim these hymns and songs to be on par with Scripture, I do believe in inspired praise in this sense, similar to how one may be moved by the Spirit in prayer using his or her own language.
[edit - It should be noted that whilst I am aware of the common arguments on both sides (which incidentally have been discussed in several threads on the Board), I am not well studied in this area, but these are my current beliefs.]