Congrats on the MP!
Unless you definitely need something Lion offers, I'd stay on snow leopard (in fact, I did, on my MP). The RAM will need some expansion, but unless you work on really intensive stuff 8 gigs should do (at least on SL), so your optimal (no loss) choice is to get 2X2 gigs for those two slots.
Unless you do GPU-heavy stuff (games, GPU-accelerated apps), the 3870 should do.
I really would not use an old HDD as system disk. In fact I strongly second using an SSD (been using SSD's as system disks since my Alu MacBook)
Those drive sleds may be quite pricey, but I understand your urge.
RGDS,
Unless you definitely need something Lion offers, I'd stay on snow leopard (in fact, I did, on my MP). The RAM will need some expansion, but unless you work on really intensive stuff 8 gigs should do (at least on SL), so your optimal (no loss) choice is to get 2X2 gigs for those two slots.
Unless you do GPU-heavy stuff (games, GPU-accelerated apps), the 3870 should do.
I really would not use an old HDD as system disk. In fact I strongly second using an SSD (been using SSD's as system disks since my Alu MacBook)
Those drive sleds may be quite pricey, but I understand your urge.
RGDS,