Source: Psalm 37:4, HCSB
Sometimes I'll read a verse in the Bible and think, "I could easily see people bending that verse to their own purposes." This is one of those verses.
There's the temptation to read this verse as, "If I serve the Lord, he'll give me the stuff I want." That attitude would not only be idolatry (placing self before God by using God as a means to an end), it would be inconsistent with the rest of Scripture.
Now I won't say that God won't bless you with stuff if you serve Him, but there's no guarantee of material goods in this verse, either.
I read this verse as an if-then statement: If our desire is first and foremost for the Lord, then He will fulfill that desire for Him. If we draw near to Him because we earnestly want to love and serve Him--and not because we believe that He'll be contractually obligated to give us wealth--then He will draw near to us and give us our heart's desires. When our first priority is serving the Lord, material possessions take a backseat to things like opportunities to glorify God, peace in the Lord, and a stronger, more mature faith.
While I certainly don't believe that praying for success is sinful, I believe it's important that we check our hearts: Why are we praying for success? Are we only praying to God when we need something? Do we look at God like a cosmic Santa Claus? Do we think God, who made the heavens and earth, owes us if we fulfill his commandments? When Nehemiah prayed for success, it was so that he could rescue his people and see God's name glorified among the nations.
This verse cuts through to the intent of the heart. I'm not saying we ever arrive at a place where our lives, talents, and efforts are wholly dedicated to God. It's a constant battle not to hold back bits and pieces for ourselves. But we should all desire to move closer to a place where we, like Jesus in the garden of Gethsemane, can earnestly say, "Not my will, but yours, God."