1 - Definitely seal that baseboard gap! Ask the landlord first, but if you do the work and give him/her the receipt for the materials I would think you should be reimbursed or have it deducted from the rent. Even if the landlord won't reimburse you, it will make a BIG difference in comfort for those drafty rooms for a little money.
2 - Have you insulated the water heater? A water heater insulation blanket can double R-value of an older heater for ~$15. The insulation blanket will reduce the heater's thermal standby losses and increase it's efficiency. This is another cheap upgrade that your landlord may reimburse you for. Here's more info -
The $15 Water Heater Upgrade | EcoDaddyo.com
Re: More efficient speakers. Your more efficient speakers may or may not reduce your electricity use depending on the type of amplifier you have. But the Klipsch speakers probably sound a lot better, so you're ahead anyhow 8*).
FWIW,
Tim