if you are pure retail and only trade fx you may want to look at Dukascopy, their spreads are very tight, pairs liquid (they have pretty decent liquidity providers), and the commission charged is lower than IB, at least last time I came across.
Dukascopy is a platform for wannabe professionals. Their spreads are not competitive, their Compliance team is a mess and their platform is awful - indeed the worst platform I ever had the "dishonor" to try out. Note: I am a buy side user and not a competitor of Dukascopy - so I am one these "real investor" guys.
You are looking for good spreads and deep liquidity? Look for brokers that cooperate with Prime of Prime banks like ABN Amro, BNP Paribas, HSBC, Barclays.
The best liquidity for retail tarders is a mixture from Sucden, LMAX and Citibank. And these are only 3 liquidity providers.
One MT4 bridge provider is offering meanwhile 68 liquidity providers. PM me for details.