I have a beginner Ibanez, and a Marshall MG 15 watt amp. I won't be getting a new amp or guitar any time soon and so I've decided to change the pickups, as the stock ones on this guitar are severely muddy, and the tone is thin.

Any suggestions?
I suspect you won't hear a huge difference, no matter what pickups you choose. Your amp is definitely contributing to your impression of your guitar's tone.
Various Strats
Polytone Mini Brute
Koch Studiotone XL
Quilter OD200, 101 Reverb and Mini
1958 National lap steel
Eastman El Rey 1
Actually I'm planning to wait until I have enough for a decent amp (Peavey Valveking), so I don't want buy another amp at the moment.
Various styles

A lot of metal at about Pantera-ish heavy, but I also like playing blues/rock n' roll a bit.
I haven't actually tried it out. I'm actually in India temporarily, but I'll be moving back to the States soon. The selection here is miserable, and what is here is rediculously overpriced.

Once i get back I'm going to buy a new amp, and I'm planning on that being a decent one like something in that (VK's) range.