"Reformed Baptists" technically denotes those Baptists who subscribe to the doctrines set forth in the 1689 London Baptist Confession of Faith. See also the Baptist Catechism. Also, since each church is autonomous, there is variation, such as disagreement over what is allowed under the Regulative Principle of Worship (instruments allowed, use of contemporary songs).

The name is a declaration of theology and church practice instead of a denomination, though many Reformed Baptist churches associate with one another. They are non-dispensational, believe in covenant theology, hold to a plurality of elders, believe in the Regulative Principle and the sufficiency of Scripture, and are 5-point Calvinists.

For more information:

The Reformed Reader
ARBCA
Founder's Conference- a mxture of Reformed and other Calvinistic Baptist churches
Johnny Farese's site

True godliness is a sincere feeling which loves God as Father as much as it fears and reverences Him as Lord, embraces His righteousness, and dreads offending Him worse than death~ Calvin