Defenders - Kompany is easy to get a hold of and is quality, plus once your team gets better you won't have to offload him as he is quality. Hyypia is easy to get as well, a bit slow but a lot better than the likes of Valeny and Stremer. Drenthe as well plays as a left back he turns out fantastic.
Midfielders - Alou Diarra is cheap and really good, good stamina and good tackler - won't score too many goals with him though. I got Edmilson as well early on which was a shock, he's quite good.
Wingers/Attacking Midfielders - Park Ji Sung is absolutely brilliant for the early years in Master League, his stamina is in the 90's so you rarely have to rotate him plus he's really quick - gets you many assists. Hofs is a good attacking midfielder I found and have never heard of, bit like Deco in the sense hes good at dribbling and can play nice through balls. I got Nani as well and no doubting he's quality.
Strikers - Not the best player you can get but Kuqi is still one of my favourites, not quick at all but wins every single header I balloon up to him, great for flicking on to wingers like Park Ji Sung who can burst down the wing, good finisher as well and scores a lot from corners. I bought Larsson as well and he scored 50 goals in his first season and a half for me, won't last long though. Djibril Cisse as well scores many for me, hes very fast despite not having the best control - hes frustrating sometimes but once you get used to him you can use him well for fast counter attacks.
Others worth noting: Aaron Lennon(RM), Faty(CB), Capdevilla(CM), Seitaridis(RB), Rivera(WG).
