For numerical analysts and scientific computing folks, a database of of 'standard problems' with given geometry, parameters, tolerances and input/output specifications, and a mechanism for storing and comparing (curated) computational attacks on these. For example, the problem of lid-driven cavity flow is considered a major test for computational fluid dynamics, and it would be great to have an agreed set of 3 or 4 sub-problems (laminar flows, angled walls, incompressible flows, nearly incompressible flow) on which the performance of algorithms could be compared.
Comparisons of the performance of algorithms on a given problem according to criteria such as accuracy, storage needed, and efficiency would be useful. Code in a given language would be useful, but one probably cannot insist on this.
There's a dearth of such 'standard problems', and thus algorithms purportedly approximating solutions for the same problem are rarely compared. NIST has an example of such standard problems for models of micromagnetics. http://www.ctcms.nist.gov/~rdm/mumag.org.html