Blender is avaliable cross platform, but utilizes OpenGL for drawing the entire interface. That means you best use a graphics card and drivers that conform to the OpenGL specifications.
Unfortunately there are a lot of cheap graphics cards on the market that only support a basic sub-set of the OpenGL specs. VIA and Intel cards are infamous for this.
The Blender developer team welcomes all efforts to bypass issues with specific configurations, but we can only support the platforms well that are in use by active coders... check this list in wiki for which platforms are in active development.
Since May 2011 we're reviewing with all branch/patch developers the status of their work, and make a migration schedule for all new features. This could include projects like new Mesh editing (BMesh), paint/sculpt improvements, Rigid Body Physics, new Curve/Nurbs system (Nurbana), Ocean Sim render, Particle Nodes, and so on.
Combining these upgrades with a redesign of shader/light system ("Cycles"), Open CL compositing, motion/camera tracking, and all the new Google Summer code projects... it'll become a massive amount of upgrades again.
Proposal is to do this in a series of small steps; with stablest branches first. We can call it the "2.6x series" resulting in a number of releases named 2.60, 2.61, 2.62 and so on. Each release is supposed to be stable, only finished branches will be added. Plan is to make a very tight schedule for this, with a bi-monthly release.
More detailed planning you can find on the "Current Projects" page:
wiki.blender.org/index.php/Dev:Doc/Projects
Branches ready for inclusion will be posted here:
http://wiki.blender.org/index.php/Dev:Ref/MergeAndIntegrationPlan
The release logs of past releases are here:
www.blender.org/development/release-logs/
Get the latest builds from Blender svn here:
builder.blender.org/download/
For Blender 2.6x the UI and general design specifications will remain on 2.5 compatible level, although there are several 2.5 leftover projects to complete still.
A related target or Blender remains to keep improving apis or modules, to enable larger groups of developers to work in parallel on projects.
Blender uses the Python programming language for its internal scripting API.
The Blender 2.5x versions feature a completely new Python API based on Python version 3.2, and is integrated deeply, used for generating Blender's GUI layouts, for import and export of external formats, and with access to all user-accessible data and functionality.
Some scripting functionality from 2.49 (pyNodes, pyConstraints, etc) is still missing however, and is pending re-design/implementation.
The Blender 2.49 Python API is now deprecated in favour of a more complete and powerful API in Blender 2.5.