I actually restarted my Gundam Collection with the 00 series.
You won't be disappointed with the four s1 00s, namely the Exia, Dynames, Arios and Virtue. Though they are NGs, they are very detailed and almost like MGs in terms of articulation and build, especially the Virtue which actually becomes the Nadleeh when the armor is removed.
You might want to hold off on the s2 00s, though the kits are nice, the articulation and details aren't really that nice, at least for me. But it's actually the 00 that started me on modifications and painting, because of that wretched lack of articulation. A lot of people are speculation that it would be the 00 and the Bushido that will have the MG or PG treatment.
Like you, I was gearing on MG only, but currently I find that getting some of the 1/144 HGUCs is also a treat, if only to pass a little bit of time, so Far, I have 3 HGUCs, and I bought the HG Wing Zero Custom since I was feeling a bit nostalgic aside from the fact that it was on sale.
Bit I do recommend getting the Sinanju. Mine's coming this weekend, at a considerably lower price.