one of the biggest problems with the big bang theory is the way all matter is so unevenly distributed: stars are climped into galaxies, galaxies are in clusters, clusters are in superclusters, and 99% of the universe is totally empty space between superclusters!
there are several "fill-in-the-gap" theories for this: dark matter, cosmic strings, etc. but one version i heard would require there to be 10 TIMES as much "dark matter" as "normal" matter!
here's the theory for planet formation:
http://en.wikipedia.org/wiki/Planet_formation
but several planets in our solar system spin the opposite direction than that theory says they should!
straw man. and a muddled understanding of big bang theory, cosmic background radiation, dark matter, dark energy, and string theory.
the clumping of matter in space has never been a problem. before dark matter and dark energy became fasionable theories (which have little to do with the clumping anyway), all that was required was an *uneven distribution* of matter and energy. the cosmos didn't have to spring into existence already pre-clumped. slight density fluctuations are enough, and gravity takes care of the rest. the cobe satellite has tentatively verified the requisite lumpyness of the cosmic background radiation. (i think that's the right name for the satellite [which if memory serves is orbiting the sun not the earth]...could be confusing it with the solar observation satellite...)
and like i said, dark matter and energy are not required for this lumpiness of matter on cosmic scales. dark matter was first invoked as a possible explanation for why the redshift indicating galactic rotation and velocities do not follow the newtonian model with distance. (contrary to popular misconception, galaxies have not been found to rotate as a "solid mass" - in fact i suspect that would require the edges of large spiral galaxies to orbit faster than light, but i haven't actually done the math. instead, it means that the slowdown of orbital velocity by distance from the center follows a different, less dramatic curve than expected by simple newtonian mechanics. i believe max fagan outlined the expected and observed formulas, you should be able to find them with a search.)
dark energy was invoked as a possible explanation for what observational evidence seems to indicate as an accelerating expansion of the observable universe. no one really has a clue what is causing it - "dark energy" is more a placeholder for some repulsive force than anything, and aren't 100% sure that the phenomenon is actually occurring...as more evidence comes in, the certainty factor will obviously increase or decrease.
string theory is an attempt to unify einstein's model of reality, with quantum mechanics, which currently don't mesh real well. it involves 11 dimensional strings, vibrating on scales so small we can't access those dimensions. (i don't remember the exact latest count of dimensions...) so far it is little more than beautiful math and has yielded no testable predictions, and doesn't seem likely to in the near future. many scientists dismiss it as non-science siphoning off valuable university research money. (i tend to feel that way to but of course am in no way qualified to defend that position against, say, a string theorist.)
hope this helps.