AV receiver: IMO, better get a unit with DTS-HD/TrueHD capability. Mga 25k - 30k+ depende sa brand and model. You may want to check out Onkyo 608/609.
Bluray player/Media Player(with hard disk) - Approx. 8k - 12k
Speaker wires and HDMI Cables: Siguro kaya na sa 1.5k
Speakers: Approx. may matitirang P26.5k. Eto ngayon ang mahirap na desisyon. Either you buy a set of entry level speakers (Look into Aaudio Ezra, Infinity, Polk Audio TSI and Wharfedale) now or just buy first a pair of higher model front speakers (Look into Aaudio Titus, B&W, JBL, Klipsch, Monitor Audio, Paradigm, Polk Audio RTI, PSB, Tannoy..etc).
Subwoofer: To follow na unless you decide to stretch your budget. For lower priced models, maganda yung Mirage. Kung medyo madagdagan ang budget, have a look at the SVS subs.
Acoustic Treatments: You'd be surprised how important these are as they have an immense impact on how your speakers will sound. Lalo na that your room is a cube (4x4 meters).
For me, kung patient ka naman and you want better sound, I'll go with the front speakers first route and from there dahan dahan mong bubuuin yung system. Tsaka may time ka rin mag-abang abang dito sa pdvd marketplace ng mga pre-owned items.
Regarding the speaker brands I suggested, audition mo na lang kasi iba iba ang pandinig natin.