Nice, well done!
To echo what jcol has already said, I'd go for the KV-1 as a first heavy then pick one of those lines, ending in either the IS7, or the IS4.
Medium-wise I'd actually recommend going either German (E50M) or American (M48A1) more than the Russians, I tend to perform better in those tanks and generally the grinds are better. The Leopard 1 is also very good, but not as welcoming as a first tier 10 medium, same goes for it's line.
For TDs, I'd suggest either Brits or Germans. Either line for the Germans will do, but depends on your play style. If you want a very good gun but not much staying power go for the new line, otherwise go for the old line (which includes the awesome Jagdtiger).
Thanks for the advice!